All Tools
Browse every tool on CacheSleuth, organized by category.
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Map Tools 33
Top ↑Convert geocoordinates between Decimal Degrees, DDM, DMS, UTM, MGRS, Plus Codes, Geohash, Maidenhead, Reverse Wherigo, and many more, with map links and elevation lookup.
Calculate coordinates from Waldmeister Reverse Wherigo codes, or create codes from cache coordinates.
Calculate coordinates from day1976 Reverse Wherigo codes, or create codes from cache coordinates.
Create geocache geoart from posted and final coordinates, validate distance rules, choose cache-type icons, and export GPX or CSV files.
Find possible geocache coordinates when one to three digits are missing from a DDM coordinate.
Batch convert GPS coordinates between DDM, DD, DMS, UTM, MGRS, Plus Code, Reverse Wherigo, OSGB, GeoHex, Geo3x3, Maidenhead, NAC, Geohash, Mercator, and antipode.
Map a list of GPS coordinates and calculate segment and total distances between points.
Calculate the distance, bearing, and midpoint between two GPS coordinates in common geocaching coordinate formats.
Project a waypoint from a GPS coordinate using a bearing and distance, then view the projected point and midpoint.
Calculate the intersection points of two circles from center coordinates and radii.
Find where two bearing lines intersect using two known coordinate points and a bearing from each.
Calculate the intersection point of three circles from center coordinates and radii.
Find where two geodesic lines intersect. Lines are drawn from A to B and C to D.
Find the antipode (the point diametrically opposite through the center of the Earth) for any GPS coordinate, with side-by-side maps of your point and its antipode.
Calculate the center, area, and perimeter of a triangle defined by three GPS coordinates.
Calculate the geographic centroid (center point) of an arbitrary list of coordinates using a 3D cartesian average.
Calculate the center point and radius of a circle passing through three GPS coordinates.
Average multiple GPS coordinate readings of the same location into a single best-estimate coordinate, with the spread of the readings.
Calculate the distance to the horizon for an observer at a given height, accounting for Earth's curvature and optional atmospheric refraction, plus the line-of-sight range to a raised object.
Convert a coordinate from one geodetic datum to another using a 7-parameter Helmert transformation, then view the shifted point on the map.
Calculate where a line defined by two GPS points intersects a circle defined by a center point and radius.
Given a line through two points and a third point off the line, find the foot of the perpendicular (the nearest point on the line), plus the cross-track and along-track distances.
Calculate the intersection of a bearing projected from one coordinate point with a line segment defined by two other coordinate points.
Calculate the geodesic area, perimeter, and centroid (center of gravity) of a polygon or quadrilateral defined by a list of coordinates.
Work out your location by measuring the compass bearing to three known coordinate points, then crossing the back-bearings to fix your position.
Calculate the rhumb line (constant compass bearing) course and distance between two coordinates, compared with the great-circle path.
Divide the line between two coordinates into a number of equal segments and list every intermediate point along the way.
Find an unknown point using two known coordinate points and a bearing from each.
Solve geocaching formulas with letter variables. Put math in square brackets, give each variable a value or a range, and get every result at once. Supports cross sums, word values, trig, roots, factorials, constants, exact modular and bitwise math, and references between formulas.
Calculate geocache coordinates from a formula with A-Z variables and bracketed math. Variables can be fixed values, ranges, or sets that expand to every combination, with each result parsed and mapped.
Calculate coordinates from the Multi Location Maze 11-character code, or create a code from cache coordinates.
Enter coordinates or use your current location to drop a draggable pin on the map. Click the map to reposition the pin.
Compute the Munroe (xkcd) geohash coordinate from a date, your graticule, and that day's Dow Jones opening, with the worldwide globalhash and an interactive map.
Code Tables 5
Top ↑Browse 300+ geocaching code tables in one place, including Pigpen, Braille, flags, fictional alphabets, symbols, and more.
Code image tool to display over 300 code tables, especially useful for geocache puzzle solving.
View every supported geocaching code table example in one place using custom text.
Snap a photo or upload an image of a single glyph from an unknown symbolic alphabet (Pigpen, Dancing Men, Aurebesh, Klingon, Daedric, dozens of constructed-language scripts and historical ciphers) and the identifier compares it against thousands of reference glyphs to suggest which code it most likely belongs to. Pairs naturally with the Code Tables to confirm and decode.
Upload a picture of a coded message written in a symbol alphabet and read it back to letters. The decoder finds each glyph, matches it against the chosen code's reference symbols, and checks the result against a dictionary and coordinate patterns. Works best on clean, evenly spaced, high-contrast images.
Cipher Tools 58
Top ↑Add a numeric key to each letter's position to shift it, a classical generalization of Caesar where the shift can vary per character. Custom alphabets supported.
German WWI field cipher (1918) combining a 5×5 Polybius square (using only ADFGX as coordinates, easy to send by Morse) with a keyword-based columnar transposition.
Successor to ADFGX with a 6×6 square that includes digits 0–9. Used by the German army in 1918 until cracked by French cryptanalyst Georges Painvin.
Each letter's position is multiplied by one key, then offset by another, modulo 26, the affine map of monoalphabetic ciphers. Caesar is the special case where the multiplier is 1.
Hebrew kabbalistic substitution cipher that splits the alphabet in half and swaps the corresponding letters of the two halves. A close cousin of Atbash.
AMSCO is an incomplete columnar transposition cipher that fills a keyword-ordered grid by alternating one and two letters per cell, then reads the columns in key order.
ASCII-85 and Base85 encoder and decoder for converting text to and from Adobe-style ASCII85.
Hebrew substitution cipher that reverses the alphabet, A↔Z, B↔Y, C↔X, appearing in the Book of Jeremiah. The simplest reciprocal cipher.
Polyalphabetic Vigenère variant that extends the keyword with the plaintext (or ciphertext) itself, so the running key never repeats. Configurable alphabets and keyword. Includes an automatic solver to crack the keyword from ciphertext.
Francis Bacon's 1605 binary cipher hides a message inside an apparently innocent text using two letterforms (or two typefaces) per letter. Includes Bacon's distinct and merged variants plus puzzle-style key options.
Reciprocal Vigenère variant where the same operation encrypts and decrypts. Named after Admiral Sir Francis Beaufort, who based it on Giovanni Sestri's earlier work. Includes an automatic solver to crack the keyword from ciphertext.
Close cousin of Beaufort that reverses the subtraction direction (key minus plaintext). Used on Confederate-era cipher disks during the American Civil War. Includes an automatic solver to crack the keyword from ciphertext.
Felix Delastelle's fractionating cipher: each letter splits into two coordinates on a 5×5 Polybius square, coordinates are interleaved across a period, and read back as new letters.
Decode book ciphers and Ottendorf-style references by selecting pages, lines, words, or characters from a pasted source text.
Reversible block-sorting transform that rearranges text into runs of similar letters. Used inside the bzip2 compressor and as a puzzle scrambler that decodes cleanly back.
Simple transposition that writes the plaintext into a rectangular grid row by row, then reads it back column by column. Quick to spot when text length is a perfect square.
Italian 19th-century swap cipher used by the Carbonari secret society in the lead-up to Italian unification, pairing letters around a central pivot.
John F. Byrne's 1918 two-disk cipher in which both alphabets permute themselves after every letter. Byrne offered cash prizes for breaking it; the algorithm wasn't published until 2010.
Plaintext is written into a grid below a keyword, then read out column by column in the order given by the keyword's letter ranks. Configurable padding and alphabet.
Auto-solves monoalphabetic substitution ciphers (Aristocrat, Patristocrat, Caesar, Atbash, keyword). Runs entirely in your browser. Lock letters to refine the result.
Columnar transposition applied twice with two different keywords. Used by Allied and Axis intelligence services through World War II for medium-grade traffic.
Configurable Enigma rotor machine simulator with 13 models, ring settings, start positions, reflectors, plugboard pairs, and foreign-character handling.
Felix Delastelle's digraph cipher that operates on letter pairs using four 5×5 squares, two filled with a keyed alphabet and two with the standard alphabet.
Plaintext is converted to Morse, regrouped in threes (with separators), then each three-symbol group is looked up in a keyed alphabet. Used by US forces in World War I.
Encrypt and decrypt the Grandpré cipher using a configurable letter grid, random homophone choices, and coordinate-pair output.
Vigenère with a numeric key (digits 0–9) instead of a letter keyword, so each plaintext letter shifts by the matching digit. Supports autokey mode and custom alphabets. Includes an automatic solver to crack the numeric key from ciphertext.
Lester Hill's 1929 polygraphic cipher: plaintext blocks are multiplied by a 2×2 matrix key modulo 26, the first cipher to operate on more than three letters at a time.
One of the earliest substitution ciphers, described in the 4th-century Sanskrit Kama Sutra. The 26 letters are paired so each letter encrypts to its partner and vice versa.
Shift each letter to a neighbor on a physical keyboard layout, left, right, up, or down. Supports QWERTY, AZERTY, and QWERTZ layouts.
Caesar shift built on a keyed alphabet: the keyword's unique letters appear first, then the rest of the alphabet, and the whole thing is rotated.
Each plaintext letter's position is multiplied by a key (coprime with 26) modulo 26, a close cousin of Caesar that scrambles instead of just shifting.
Encode plaintext into Morbit cipher digits, or decode Morbit ciphertext back to text, using a 9-letter keyword or 1-9 permutation key.
Russian Nihilist cipher combining a Polybius square with a numeric keyword. Each plaintext letter and each keyword letter are converted to two-digit Polybius coordinates and added together to produce the ciphertext.
Encode and decode numeric homophonic ciphers with an A-Z key where each letter may map to one or more exact number tokens.
The only mathematically unbreakable cipher when the key is truly random, as long as the message, and used exactly once. Generate a fresh pad or supply your own.
Italian Renaissance cipher developed by Pope Innocent X's secretary Matteo Argenti and named after the Pizzini family, where letters map to numbered positions in a keyed grid.
Charles Wheatstone's 1854 digraph cipher worked on letter pairs using a keyed 5×5 grid. Adopted by the British in the Boer War and World War I.
Morse-based cipher in which dots, dashes, and separators are each replaced by one of several substitute characters, masking the underlying Morse pattern.
Each letter is encoded as the row/column coordinates of its position in a 5×5 (letters) or 6×6 (letters + digits) grid. Supports keyed alphabets and custom coordinate labels.
Giovanni Battista della Porta's 1563 reciprocal polyalphabetic cipher. The keyword chooses one of 13 alphabet pairings, and the same operation encrypts and decrypts. Includes an automatic solver to crack the keyword from ciphertext.
Ragbaby is a keyed periodic substitution cipher. A keyword builds a 24 letter mixed alphabet, then every letter is shifted forward by a number that counts up across the words of the message.
Write the plaintext zig-zagging down and up across a chosen number of rails, then read it off row by row. Configurable rail count and starting offset.
Educational RC4 stream cipher. Enter a key to generate a pseudo-random keystream and XOR it with your text. Output as hex or Base64. Encryption and decryption are the same operation.
Shift each letter by a chosen amount, with one-click presets for ROT13, ROT5, ROT18, and ROT47 covering letters, digits, and the full printable ASCII range.
Rotate text written into a grid 90° left or right, handy for puzzle text laid out in non-standard reading orders. Configurable column count and padding.
Caesar-style rotation that lets you choose exactly which characters get shifted and which pass through untouched. Useful for puzzles that mix cipher and plain text.
Writes the plaintext into a grid and reads it back along a chosen path (spiral, diagonal, or zig-zag) instead of plain columns.
Educational RSA demo using tiny primes and BigInt math. Generate a key pair from two primes, then encrypt and decrypt text or a single number. For learning and puzzles only, not for real security.
Vigenère-style cipher where the key is a long passage of natural text (a book, a poem) rather than a short repeated keyword, defeating standard Kasiski analysis.
Ancient Spartan transposition cipher: text wrapped around a cylinder of a specific diameter, then unwrapped, scrambles into a regular column rotation.
Solitaire (Pontifex) is a hand cipher designed by Bruce Schneier that uses an ordered deck of 54 cards, including two jokers, to generate a keystream for encrypting and decrypting messages.
Soviet-era fractionating cipher mapping common letters to single digits and rare ones to two-digit codes. Often used as an additive over a one-time pad in VIC-style ciphers.
Map each plaintext letter to a custom target letter using a keyed alphabet, the foundation under almost every monoalphabetic cipher in this list.
Felix Delastelle's three-dimensional extension of Bifid. Each letter gets three coordinates from a 27-character cube, interleaved across a period before being read back.
Johannes Trithemius's 1508 progressive Caesar, each letter shifting by one more than the previous. The first published polyalphabetic cipher and the direct ancestor of Vigenère.
German WWI double columnar transposition variant. Famously broken by French cryptanalysts in 1914 within weeks of its introduction.
The classic 1553 polyalphabetic cipher: each plaintext letter is Caesar-shifted by the corresponding letter of a repeating keyword. Considered unbreakable for three centuries. Includes an automatic solver to crack the keyword from ciphertext.
Soviet KGB hand cipher used by spy Reino Häyhänen in the 1950s, combining a straddling checkerboard, two transpositions, and a daily key. The strongest hand cipher ever fielded.
Code Tools 44
Top ↑Geocaching code that maps each letter to a unique three-symbol group. Supports the canonical alphabet, custom carriers, or auto-detected three-character patterns.
Find every word and multi-word phrase that can be made from a set of letters. Multi-word phrase anagrams, single-word anagrams, and a 'words from these letters' subset mode. Toggle between a common-words dictionary and a 235,000-word full dictionary. Solves instantly in your browser, no server round-trips.
Three-character code built from forward slash, pipe, and backslash symbols. Each letter is encoded as a group of three; supports custom carriers and auto-detection.
The 5-bit telegraph codes that preceded ASCII, ITA1 (Baudot) on early teleprinters and ITA2 (Baudot–Murray) on Western Union and TWX networks.
Convert words to the calculator numbers that spell them upside down, or flip a number to read the hidden word. Uses the classic seven-segment letters from the word BEGHILOS.
Convert between text, Brainf*ck, Ook!, and Short Ook! code, with a small interpreter.
Geocaching code that represents each letter as a small grid of dashes and pipes, visually similar to Chinese hanzi strokes, hence the name.
Encodes letters as clock-face hours with AM/PM markers and "00" as a word separator. Often appears in geocaching puzzles using clock imagery.
Encode text as colored-squares blocks where each square has a binary value (1, 2, 4, 8, 16) summing to a letter A-Z. Recolor every value, toggle numbers, resize blocks, and export a PNG or share link for geocaching puzzles.
Convert text to COW code and execute COW programs back into text.
Ten-bit punched-card-style code where each character is a binary string. Output can be ASCII text or the equivalent decimal numbers.
DTMF (Dual-Tone Multi-Frequency) maps each phone-keypad press to a pair of audio frequencies. Only the 16 keypad characters are valid input: digits 0-9, letters A-D, *, and #. Any other character in the plaintext (letters E-Z, spaces, punctuation) is silently dropped.
Convert text typed on one keyboard layout as if it had been typed on the other (QWERTY ↔ Dvorak). Useful when puzzle text was prepared on the wrong layout.
Count enclosed areas in uppercase letters, lowercase letters, and numbers with open or closed 4 handling.
Cooke and Wheatstone's 1837 telegraph used five magnetic needles pointing left or right to spell out one of 20 letters across two wires.
The substitution cipher from Edgar Allan Poe's 1843 short story "The Gold-Bug," where the buried-treasure cryptogram is solved by frequency analysis on the page.
Translates each letter to a unique syllable in the Hodor language from HBO's Game of Thrones, where the character can only say his own name.
Three-character syllabic code based on the muffled speech of Kenny McCormick from South Park, mapping each letter to a sequence of m/f/p sounds.
Convert letters to numbers and numbers back to letters using A=1 through Z=26.
International Morse code with optional puzzle variants: reverse the sequence, swap dots and dashes, or both. Common transformations in mystery caches.
Decode run-on Morse code without separators by branching possible letter groupings and exploring viable translations.
Encode text to Nak Nak code and decode Nak syllables back to text.
Encode and decode messages with the World War II Navajo code talkers' alphabet, where each English letter is spoken as a Navajo word whose English meaning starts with that letter.
Convert letters or keypad line number paths into Number Pad Lines images.
PLANET (Postal Alpha Numeric Encoding Technique) maps each digit 0-9 to a 5-bar short/tall (i/I) pattern, framed by tall bars. Auto-detects two non-standard symbols (e.g. ./|, a/b, x/o) and tries both orientations.
POSTNET (Postal Numeric Encoding Technique) maps each digit 0-9 to a 5-bar short/tall (i/I) pattern, framed by tall bars. Auto-detects two non-standard symbols (e.g. ./|, a/b, x/o) and tries both orientations.
Encode and decode internationalized domain names with RFC 3492 Punycode. Unicode labels become ASCII with an xn-- prefix, and back again.
A nine-segment digital display alphabet, think calculator-style segments extended to cover the full alphabet. Includes matching symbol images for each character.
Convert Qwerty keyboard characters to row and column coordinate pairs.
Shift letters, numbers, and optional special characters across Qwerty keyboard rows.
Encode and decode strings written in segment-display notation. Each character is described by the set of segment labels (A, B, C, …) that are lit. Supports 7-, 9-, 14-, and 16-segment displays.
Code in which each letter is encoded as a group of slashes and pipes ( / and | ). A common building block in geocaching cipher puzzles.
Text steganography that disguises a secret message as spam-style prose, a fake PGP armor block, or a run of spaces and tabs. Optional password layer. Encode and decode entirely in your browser.
Convert text to and from spelling-alphabet code words. Includes the NATO/ICAO alphabet (Alfa, Bravo, Charlie), police (Adam, Boy, Charles), Western Union, RAF, Able Baker, and Dutch, German, Swedish, and Russian variants.
Decode or encode the Spirit Mars rover DVD code, a variable-length line and dash alphabet used on The Planetary Society DVD carried by Spirit.
Convert Tap Code between letters, numeric row-column pairs, and dot groups.
Encode and decode the TAPIR substitution table used by the DDR MfS and NVA, including the numeric mode used for digits and punctuation.
Drum-language code that uses forward slashes and backslashes to represent letters as drumbeat patterns, adapted from African talking-drum traditions.
Find dictionary words from T9 predictive text digit sequences.
Flip text upside down using Unicode characters that resemble rotated letters, numbers, and punctuation. Flip a message, then unflip it to read the original.
Old-style mobile phone keypad text input: 2=A, 22=B, 222=C, 3=D, etc. Decodes from repeated key presses, key/position pairs, or directional sequences.
Render Logo-style vector path commands such as FD, BK, LT, RT, PU, and PD as an inspectable SVG drawing for geocaching puzzles, with text encoding, rotation, flips, export, and share links.
Encode letters, numbers, and punctuation as ITA2/Baudot-style five-bit color blocks in an X&Y-inspired visual code, with PNG/SVG export and share links for geocaching puzzles.
Turn plain text into glitchy Zalgo text by stacking Unicode combining diacritical marks, with an intensity control. Clean Zalgo text back to readable characters.
Number Tools 60
Top ↑Two different numbers are amicable when each one equals the sum of the other's proper divisors, like 220 and 284. Check any number to find its amicable partner if it has one, or list every amicable pair up to a limit for puzzle use.
An Armstrong (or narcissistic) number equals the sum of each of its digits raised to the power of the digit count, like 153 = 1^3 + 5^3 + 3^3. Check any number to see its full digit-power breakdown and verdict, or list every Armstrong number up to a limit for puzzle use.
Convert text and characters between ASCII/Unicode, decimal, hexadecimal, octal, binary, Unicode notation (U+0041), and HTML numeric entities (A and A). Type into any field and the others update live.
An automorphic number is one whose square ends in the number itself, like 76 because 76 squared is 5776. Check any number to see its square with the matching tail highlighted and the verdict, or list every automorphic number up to a limit for puzzle use.
Encode and decode Babylonian numerals, the sexagesimal (base 60) system of stacked tens and units wedges. Enter a number to see its cuneiform glyphs and place values, or read a numeral back to decimal.
Encode positive whole decimal numbers as Binary-Coded Decimal nibbles, or decode BCD bit groups back to decimal digits for geocaching and logic puzzles.
Barcode number pattern converter for digits 0 through 9.
Convert integers between bases 2 through 62.
Encode and decode Base100 emoji streams. Each UTF-8 byte maps to one emoji codepoint in the canonical U+1F3F7 to U+1F4F6 range.
Encode and decode text using the standard RFC 4648 Base32 alphabet (A–Z, 2–7). Often seen in TOTP secrets, QR codes, and DNS-safe identifiers.
Encode and decode text using Base58. Choose between the Bitcoin alphabet (123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz) and the Flickr alphabet (lowercase before uppercase). Base58 omits visually ambiguous characters like 0, O, I, and l.
Encode and decode text using Base62. Supports both 0-9A-Za-z and 0-9a-zA-Z alphabet orderings.
Base64 encoder and decoder for text.
A large integer calculator for decimal, hexadecimal, octal, and binary values with standard arithmetic, modular arithmetic, bitwise operations, powers, and modular inverse.
Catalan numbers count many things: valid bracket sequences, binary trees, polygon triangulations, and more. List the first terms, look up C(n) for any index, or test whether a number is a Catalan number and see its index. Computed with arbitrary precision.
The Collatz conjecture, also called the 3n+1 problem, repeatedly halves even numbers and turns odd numbers into 3n+1 until reaching 1. Trace the full hailstone sequence for any starting number, see its step count and peak value, or search for the starter with the longest sequence up to a limit.
Replace a number with the sum of the factorials of its digits, then repeat. The chain either lands on a fixed point called a factorion, falls into a number that is itself a factorion, or settles into a repeating cycle. In base 10 there are exactly four factorions: 1, 2, 145, and 40585. Trace the chain for any number and see its outcome.
Figurate numbers count dots arranged into regular shapes. Pick a type (triangular, square, pentagonal, hexagonal, or tetrahedral), list the first terms, look up the value at a given index, or test whether a number belongs to that family and see its index.
A Harshad (or Niven) number is one that is divisible by the sum of its own digits, like 18 which has digit sum 9 and 18 divided by 9 is 2. Check any number to see its digit sum, quotient, and verdict, or list every Harshad number up to a limit for puzzle use.
Kaprekar's routine sorts a number's digits high to low and low to high, then subtracts, and repeats until it locks onto 6174 for four digits or 495 for three digits. Trace the chain and step count for any number, and separately check or list Kaprekar numbers, whose squares split into two parts that add back to the number.
The reverse-and-add process flips a number's digits and adds it to itself, repeating until the result reads the same forwards and backwards. Most numbers reach a palindrome quickly, but some, like 196, resist for thousands of steps and are called Lychrel candidates. Trace the chain, palindrome, and iteration count for any number.
A Mersenne number is M(n) = 2 to the n, minus 1. List M(n) for a range of exponents and see which are Mersenne primes, look up M(n) for any exponent, or test whether a number is one less than a power of two and report its exponent. Computed with arbitrary precision.
A standalone integer number cruncher for geocaching puzzles: inspect parity, primality, factors, special number forms, base conversions, and evaluate BigInt worksheet expressions with variables and modular arithmetic helpers.
Encode and decode Cistercian numerals, the medieval monastic system that packs any number from 0 to 9999 into a single glyph built around one vertical stem. Enter a number to draw its glyph, or read the four positional digits back to decimal.
Calculate the angle between the hour and minute hands for any time, or find every time that matches a given angle.
Solve cryptarithm and alphametic puzzles by assigning unique digits to letters in arithmetic equations and optional logical conditions.
Add or subtract days, weeks, months, and years from a date with leap-year aware Gregorian calendar math for puzzle deadlines, cache anniversaries, and date clues.
Calculate the exact number of days between two Gregorian calendar dates, with signed direction, absolute distance, inclusive span, and week/day breakdown.
Calculate the day of the week for a date, plus its day number within the year and leap-year status, using proleptic Gregorian calendar rules.
Digital root calculator using several letter value systems.
Convert decimal numbers to and from the D'ni base-25 number system from Cyan's Myst series. Type a number or tap the D'ni keypad to see the symbols rendered in the D'ni font, with a power-of-25 breakdown for geocaching puzzles.
Euler-Mascheroni constant digit lookup and search helper.
Euler number digit lookup and search helper.
Fibonacci number generator and lookup tool.
Decimal to fraction approximation helper.
Convert between geocache GC codes (e.g. GC2J3WZ) and the underlying numeric cache IDs that geocaching.com uses internally.
Golden ratio digit lookup and search helper.
Convert numbers between decimal, standard binary, and reflected binary Gray code. Gray code is an ordering of binary where two successive values differ in only one bit.
A happy number is one that eventually reaches 1 when you repeatedly replace it with the sum of the squares of its digits. Check any number to see its full digit-square chain and verdict, or list every happy number up to a limit for puzzle use.
Convert calendar date/time values to Julian Day numbers and back, including JPL-style month names, day-of-year input, decimal day/time forms, astronomical years, Modified Julian Date, and Unix time.
Lucas number generator and lookup tool.
Encode and decode Maya numerals, the base-20 system of dots, bars, and a shell for zero. Enter a number to see its stacked glyphs and place values, or read a numeral back to decimal.
Calculate today's day number, convert a full date or month/day pair to an nth day of the year, and convert a day number back to a calendar date.
Four conversions in one tool: alphabetical index → number word, number word → alphabetical index, number → English spelling, and spelled-out English → integer. The alphabetical order uses the standard 0–100 ranking where eight = 1, eighteen = 2, eighty = 3, and zero = 101.
Convert numbers to written English words, or parse spelled-out numbers back to digits.
Reduce each letter of a word or phrase to a digit using the Pythagorean (1–9 cycle), Pythagorean (1–0 cycle), or Chaldean systems, then sum and reduce to a single-digit numerology value or digital root.
A perfect number equals the sum of its proper divisors, like 28 = 1 + 2 + 4 + 7 + 14. When that sum is larger the number is abundant, and when it is smaller the number is deficient. Check any number to see its proper divisors, their sum, and the classification, or list every perfect number up to a limit.
Pi digit lookup and search helper.
Prime number list and factorization helper.
A pronic number, also called an oblong number, is the product of two consecutive integers: P(n) = n(n+1). List the first terms, look up P(n) for any index, or test whether a number is pronic and report its index. Computed with arbitrary precision.
Square root of 2 digit lookup and search helper.
Roman numeral converter for values 1 through 3999.
Shadoks number converter using GA BU ZO MEU.
Temperature conversion calculator.
Square root of 3 digit lookup and search helper.
Convert clock times to total seconds since midnight and the percentage of the day elapsed. Useful for puzzles that encode coordinates as times.
Triangle side angle area and perimeter calculator from three known attributes.
UTF-8 text to hex encoder and decoder.
Expanded unit conversion calculator with lookup-table style results across many measurement categories.
Word and letter value calculator with A1Z26, phone keypad vanity, Scrabble (Dutch, English, German), cyclic tables, and diacritic-extended alphabets, plus diacritic normalization.
Image & File Forensics 17
Top ↑Upload an animated GIF of a blinking light or flashing signal and decode it into Morse code, then plain text. Brightness per frame is measured and timed automatically, with sliders to fine tune the on or off threshold and the dot or dash split.
Upload a recording of Morse code beeps or listen live through your microphone and decode it into Morse and plain text. The dominant tone frequency and the timing are detected automatically, with sliders to fine tune the frequency, threshold, and dot or dash split.
Create barcodes in Code 128, Code 39, and EAN-13 formats with configurable size and colors.
Render binary into a picture: 1 bit per pixel black and white, or one byte per pixel grayscale. You can also upload an image and read its pixels back out as a row-major 0/1 bitstream with byte views.
Upload a picture of a coded message written in a symbol alphabet and read it back to letters. The decoder finds each glyph, matches it against the chosen code's reference symbols, and checks the result against a dictionary and coordinate patterns. Works best on clean, evenly spaced, high-contrast images.
Upload an image file to read EXIF data. Supports JPEG, PNG, WebP, TIFF, HEIC/HEIF, AVIF and limited GIF support.
Upload a file and this tool scans every byte for known file-type signatures hidden inside it, including extra data appended after the end of an image. Carve out each find and download it as its own file.
Upload an animated GIF, WebP, APNG, or AVIF and split it into individual frames. View every frame side by side, inspect timing and dimensions, and download frames individually or as a ZIP.
View any file as a hex dump with offsets, raw bytes, and an ASCII column. Extract printable strings from the whole file to surface hidden coordinates or clues.
Non-destructive image color and pixel tools that reveal faint or hidden marks. Tweak brightness, contrast, saturation, hue, invert, threshold, isolate a channel, view a single bit plane, and flip, rotate, or stretch the picture.
Hide text inside an image by tweaking the least-significant bits of its pixels, then download a lossless PNG. Reveal hidden messages from a stego image, with an automatic header read plus a raw LSB extraction mode for foreign puzzles.
Upload a Magic Eye style autostereogram and reveal the hidden depth shape without crossing your eyes. Auto-detects the repeat period, then maps the match between the image and a shifted copy of itself into a visible figure.
Create a wall-eyed text autostereogram (ASCII magic eye). Type a hidden message, pick random characters or real words for the background, and generate a block of monospace text whose secret words pop out at a different depth when you relax your eyes. Export as plain text or as a fixed-width monospace PNG.
Create a custom QR code with configurable text, size, quality level, foreground, and background.
Upload a QR code image file and scan the encoded text.
Encode and decode Tupper's self-referential formula. Convert text, drawings, or images into the integer k for geocaching puzzle caches, and decode k back into a bitmap.
Split a black-and-white secret image into two share images using a 2-out-of-2 visual secret sharing scheme. Each share looks like random noise on its own, but overlaying the two reveals the hidden picture.
Misc Tools 20
Top ↑Paste cipher text and run 250+ decoders at once, Caesar, Vigenère, Atbash, Bacon, Polybius, Beaufort, Playfair, ADFGX, Morse, Base64, and dozens more, with optional keyword, alphabet, and number hints. Detects coordinates in multiple notations, surfaces possible plaintext words, and groups results by likelihood so the right answer rises to the top.
Manipulate text for puzzle solving with case changes, filtering, reversing, grouping, ROT transforms, replacement, file loading, saving, and content analysis.
Analyze character frequencies, word counts, letter counts, number counts, and symbol counts in a body of text.
An interactive flowchart that walks through clues in puzzle text (letter patterns, character sets, common encodings) and points you toward the most likely solver.
Encode HTML or text into JavaScript document.write output.
Paste any symbol to identify its Unicode name, codepoint, HTML entity, Alt code, and puzzle-solving hints. Search by name, browse categories, compare confusable characters, and analyze symbol-heavy puzzle text.
Unicode character lookup tool that maps each character in a message to its Unicode code point and name.
Copyable HTML examples for creating geocache pages, including paragraphs, line breaks, centering, text styling, links, images, sizing, inline styling, and divs.
Make your own printable geocache log sheets and log rolls sized to fit nano, bison tube, film canister, petling, and custom containers. Add a cache name, GC code, your own logo image, pick columns and line styles, optionally add a finder note for muggles, then save as PDF or PNG. Everything runs in your browser, nothing is uploaded.
Bookmarklets that send highlighted text into the Multi Decoder, Multi Encoder, Cipher Identifier, Cryptogram Solver, Anagram Solver, Frequency Analysis, Unicode tool, and code tables, scrape every coordinate off a page onto the Map Coordinates List, plus shortcuts for coordinate conversion, GC/TB lookup, CacheSleuth search, text manipulation, geocaching user search, keyword search, and GeoCheck captcha entry.
Convert ISBN-10 to ISBN-13 or ISBN-13 to ISBN-10, and look up ISBN details through Open Library with Amazon and Google fallback searches.
Generate MD5, SHA-1, SHA-256, SHA-384, SHA-512, SHA-512/224, and SHA-512/256 hashes for text.
Decode resistor color bands into resistance and tolerance values using the standard color code table.
Convert element atomic numbers to symbols and names, or convert symbols and names back to atomic numbers.
Spell words with chemical element symbols and view matching periodic table tiles.
Translate text to and from CacheSleuth DNA code triplets using A, C, G, and T.
Convert DNA or RNA sequences into amino acid sequences, inspect codons, and look up standard genetic code mappings.
Decode and create Draw A Stickman Episode 1 custom message URLs.
Convert a plain English message into Pig Latin.
Translate text into Circular Gallifreyan and save the generated artwork as an image.
Games & Solvers 28
Top ↑Browse game caches and interactive puzzle pages created by CacheSleuth.
Enter the given 0s and 1s of a Binairo puzzle, also called Takuzu or Binary Puzzle, then solve the grid so each row and column holds equal counts of each digit, never three of the same digit in a row, and no two rows or columns alike. Click cells to set them and solve grids from 4 by 4 up to 10 by 10.
Place the islands of a Bridges puzzle, also called Hashiwokakero or Hashi, with their numbers and solve it so the islands are joined by straight bridges that never cross, with at most two bridges between a pair, each island carrying exactly its number of bridges, and the whole network connected. Click cells to set island numbers and solve grids up to 9 by 9.
Flip a coin, guess heads or tails, and track wins, losses, and choices.
Enter a Futoshiki puzzle, also called Hutoshiki or More or Less, by typing any given digits and clicking the greater-than and less-than signs between cells, then solve the Latin square so every row and column holds each number once while every inequality stays true. Works for grids from 4 by 4 up to 7 by 7.
An interactive Conway's Game of Life playground. Paint cells on a grid, step or play the B3/S23 simulation, and load patterns like the Glider, Blinker, Pulsar, and Gosper glider gun.
Build a Heyawake puzzle by carving the board into rooms and giving some rooms a black-cell count, then solve it so every numbered room holds exactly that many painted cells, painted cells never touch, the white cells stay connected, and no straight run of white cells crosses more than two rooms.
Type the number grid of a Hitori puzzle and solve it to find which cells to shade so that no number repeats among the unshaded cells of any row or column, no two shaded cells touch edge to edge, and all the unshaded cells stay connected. Works for grids from 4 by 4 up to 8 by 8.
Build a Kakuro puzzle, also called cross-sums, by marking the block cells and typing each across and down run total, then solve so every white cell holds a digit 1 to 9, each run uses different digits, and each run adds up to its clue. Works for grids up to 8 by 8 with a clickable block and clue editor.
Build a KenKen puzzle, also called Mathdoku or Calcudoku, by drawing its cages and entering each cage target and operation, then solve the Latin square so every row and column holds each number once and every cage hits its arithmetic target. Works for grids from 3 by 3 up to 7 by 7.
Build a Light Up puzzle, also called Akari, by marking the walls and their numbers, then solve it to place bulbs so every white cell is lit, no two bulbs shine on each other, and each numbered wall touches exactly that many bulbs. Click cells to set walls and numbers and solve grids up to 8 by 8.
Interactive logic grid solver for zebra and Einstein style puzzles. Set up your categories and items, mark relationships or enter clues, and watch it auto-deduce every forced cell across the grid.
Enter the known numbers of a magic square and solve the rest so that the whole square uses the distinct numbers 1 to n squared and every row, every column, and both diagonals add up to the same magic constant. Works for squares from 3 by 3 up to 5 by 5, completing the cells you leave blank.
Enter the guesses you have made and the black and white peg feedback for each, and the solver lists every code still possible and suggests the strongest next guess using a worst case minimizing strategy. Works for any number of positions and colors, with or without repeated colors.
Place the white and black pearls of a Masyu puzzle, also called Pearl, and solve it to draw the single closed loop through the cell centres. The loop runs straight through every white pearl and turns at every black pearl, with the matching turn and straight rules on the neighbouring cells. Works for grids up to 8 by 8.
Enter the row and column number clues of a nonogram, also called picross or griddler, and solve the hidden picture. The solver fills every cell that logic forces and falls back to a search when a puzzle needs a guess.
Enter a number pyramid, also called a number wall, with some blocks left blank, and the solver fills the rest. Every block equals the sum of the two blocks directly beneath it.
Type the numbered endpoints of a Numberlink puzzle, also called Arukone or Flow, and solve it to connect each pair with a path. The paths never cross or overlap and together fill every cell of the grid. Works for grids up to 8 by 8 with up to a dozen number pairs.
Type the island clues of a Nurikabe puzzle, also called Islands in the Stream, and solve it to shade the black sea. Every numbered cell becomes a white island of exactly that size, islands never touch, the sea is one connected region, and the sea has no 2 by 2 block. Works for grids up to 8 by 8.
Roll one or more six-sided dice with running totals. For chance-driven puzzles or just for fun.
Type the word you played and set each tile's premium square and any blanks to get the exact play score. Supports Scrabble English and Words With Friends tile values plus the all-tiles bingo bonus.
Enter the cards laid out in a game of SET by their number, color, shading, and shape, and the solver finds every valid set, where each of the four features is either all the same or all different across the three cards. Each found set is drawn out so you can spot it on the table.
Enter a Skyscrapers puzzle, the Latin square where edge numbers tell you how many buildings are visible looking down each row and column, then solve it so every row and column holds each height once and every clue is satisfied. Type the clues around the grid, add any given heights, and solve grids from 4 by 4 up to 7 by 7.
Type the number clues of a Slitherlink puzzle, also called Loop the Loop or Fences, and solve it to draw the single closed loop along the grid edges so that each numbered cell has exactly that many of its four sides on the loop. Works for grids up to 7 by 7 with a simple clue grid.
HTML Sudoku solver with hints, allowed values, singles, undo, reset, and serial puzzle loading.
Pick the number of disks and the peg labels, then get the full minimum move sequence for the Tower of Hanoi. The list shows every step in order and an animation walks through the solution.
Generate a word search grid from a list of words with optional diagonals and reversed words, or paste a grid and a word list to find where each word hides. Runs entirely in your browser.
Paste a nine by nine wordoku grid built from nine distinct letters and solve it with a backtracking sudoku engine. The solver also lists the diagonals and rows so you can spot the hidden themed word.
Reference 4
Top ↑Reference Lists on CacheSleuth.
Transportation Codes on CacheSleuth.
Browse external puzzle, cipher, coordinate, checker, app, podcast, and geocaching reference links, grouped by category.
Look up geocaching words, phrases, abbreviations, and acronyms.