Geocaching puzzle solver
Decoders, coordinate tools and a cipher cheat sheet for mystery caches. Everything runs on your device.
ROT13 is its own inverse. Run the output through again and the original comes back.
Show the steps
Choose a conversion
Puzzle tools
19 converters in 2 groups
- Hint decoderYbbx [Rock]becomesLook [Rock]ROT13 for cache hints, with [bracketed] words left alone.
- GPS coordinate converter32.70205becomesN 32° 42.123DDM, decimal degrees and DMS from one paste, each with a copy button.
- Waypoint projection250 m at 70°becomesnew pointGo a distance on a bearing, or measure between two points, on the WGS84 ellipsoid.
- Word value calculatorGEOCACHEbecomes47Letter sums, digital roots, coordinate checksums and keypad digits.
- Cipher identifierURYYBbecomeswhich cipher?Paste something unreadable and we work out what it is.
- ROT13HELLObecomesURYYBRotate every letter by 13. The same step encodes and decodes.
- Caesar cipherHELLObecomesKHOORAny shift from 1 to 25, with automatic shift detection.
- Morse codeSOSbecomes... --- ...Text to dots and dashes, with sound and light.
- BinaryHbecomes01001000Text to 0s and 1s and back.
- HexHibecomes48 69Text to hexadecimal bytes and back.
- A1Z26 cipherHIbecomes8-9A is 1 and Z is 26. The simplest way to write letters as numbers.
- Vigenère cipherATTACKbecomesIHSQIRA shift that changes with every letter, set by a keyword.
- AtbashHELLObecomesSVOOLReverse the alphabet: A becomes Z, B becomes Y.
- Pigpen cipherAbecomesdrawnThe Freemasons' grid cipher, drawn as symbols you can download.
- Polybius squareHIbecomes23 24Turn each letter into the row and column it occupies in a 5x5 grid.
- Bacon's cipherAbecomesAAAAAFive As and Bs per letter. A binary alphabet, published in 1623.
- Roman numerals2026becomesMMXXVINumbers and years to Roman numerals and back.
- NATO phonetic alphabetHIbecomesHotel IndiaAlfa to Zulu, both ways, with the chart.
- Base64SGk=becomesHiDecode the A–Z, 0–9, + and / strings that end in = signs.
Nothing here matches that. If you're holding text you can't read, the cipher identifier tries every converter on it.
What a mystery cache is
Most geocaches are at the coordinates on their listing. A mystery cache, the type marked with a question mark and listed as an Unknown Cache, isn't. The posted coordinates are a starting point, and the real ones are hidden in a puzzle: a cipher, a picture, a sum, sometimes a single odd word in the description.
The tools here cover the parts that turn up again and again. The hint decoder reads the scrambled hint. The coordinate converter and waypoint projection handle the numbers once you have them, and the decoders below cover the classic ciphers. All of them run on your device, so a half-solved puzzle never leaves it, and they keep working under trees with no signal once the page has loaded.
How to approach a mystery cache
Start with the title and every word of the description, then the page source. Owners hide text in white-on-white, in HTML comments and in image names. Look at the attributes and any pictures too.
Then identify what you've found. The cheat sheet below covers the common ciphers by sight; for anything else, paste it into the cipher identifier, which tries the shifts, Atbash and the usual encodings and ranks them by how much each reads like English.
Decode, then check the answer before you walk. A puzzle's final is normally close to the posted coordinates, so measure the distance between the two with the projection page's Two points mode; a final 400 km away means a slip somewhere. If the owner gives a checksum, the word value calculator takes it. Last, if the listing links a checker, use it. It's the only thing that knows the answer.
What is this cipher? A cheat sheet
| What you see | Example | Probably |
|---|---|---|
| Only 0s and 1s, often in groups of eight | 01001000 01101001 | Binary |
| Dots and dashes, or two symbols standing in for them | ... --- ... | Morse code |
| Digits 0–9 and letters A–F only, in pairs | 48 69 21 | Hexadecimal |
| A–Z, a–z, 0–9, + and /, often ending in = or == | Q2FjaGU= | Base64 |
| Numbers from 1 to 26 and nothing higher | 3-1-3-8-5 | A1Z26 (letter numbers) |
| Two-digit numbers using only the digits 1 to 5 | 13 11 13 23 15 | Polybius square |
| Groups of dots, or knocks, in pairs of one to five | .. ... .. .... | Tap code |
| Groups of five made of only A and B | AABBB ABAAA | Bacon cipher |
| Only the letters I, V, X, L, C, D and M | X IV MMXXVI | Roman numerals |
| Real-looking letters and word lengths, but no words | SVAQ GUR PNPUR | ROT13 or another Caesar shift |
| Like a shift, but none of the 25 shifts reads | URMW GSV XZXSV | Atbash |
| Letters only, and neither a shift nor Atbash reads | LMBJ XVK GOILS | Vigenère (needs a key) |
| Grid corners and V shapes, some with dots | Pigpen |
What is this cipher? A cheat sheetstringmash.com/geocaching
From answers to coordinates
Many puzzles end in a template like `N 32° 4A.BCD W 117° 0E.FGH`, with each letter an answer to work out. Write the answers down before filling the template in, and keep the zeros. A longitude of `09.456` minutes isn't `9.456` until it's typed, and a misplaced digit there moves the final by kilometres.
When the puzzle gives a distance and a bearing instead, project it from the posted coordinates or from a waypoint you've found, and note whether the distance is in feet or metres.
Questions
How far from the posted coordinates is the final usually?
Close by, normally within walking or a short drive. Each listing site sets its own limit, so check its guidelines. If your answer is far away, recheck the decoding before you set out.
What's the quickest way to identify a cipher?
Look at the characters. Only 0 and 1 is binary, dots and dashes are Morse, and letters with real-looking word lengths are usually a shift. The cheat sheet on this page has the rest, and the cipher identifier will test a pasted message for you.
Do these tools send my puzzle anywhere?
No. Every conversion runs in your browser. The only exception is a map link, which sends a coordinate to that app or site if you tap it.
Can I use them in the field?
Yes. The pages work at phone width with large copy buttons, and once a page has loaded its tool works without signal.
Sources
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