Paste a coded quote into this cryptogram solver and work through the key letter by letter, with the decoded text updating as you type. When you get stuck, Auto solve matches the shapes of the coded words against the dictionary and fills in the most likely key, keeping any letters you have locked.
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How to use the cryptogram solver
- Paste or type the coded text into the box. Punctuation and spaces stay where they are.
- Under Your key, each code letter in the puzzle has a box. Type the real letter you think it stands for. The text above shows your guess on top and the code letter underneath.
- Press Lock on any letter you are sure of.
- Press Auto solve to fill in the rest. It keeps your locked letters and may change the others.
If two code letters are given the same real letter, both turn red, since each letter in a substitution cipher stands for exactly one other. Open "Plain text and letter counts" to read the decoded text on one line and see how often each code letter appears.
How Auto solve works
Every word has a shape made by its repeated letters. In a substitution cipher the shape never changes, so a coded word like XYZZY can only be a real word with the same pattern of repeats. The solver lists every dictionary word with the right shape for each coded word, starting with everyday words.
Then it searches for one key that fits them all. It always works next on the word with the fewest options left, often a long word or one with doubled letters, and backs up when a choice leads nowhere. If a word fits nothing (a name, say), the solver leaves it unsolved and carries on with the rest. The search runs for about two seconds and returns the best key it found.
Worked example
Paste this in and press Auto solve:
UQYXDRYU ISJDXV FHUKR HKYQVV XDR FHYW VWG QU KQIF HUF NASRX USJDXV.
The solver comes back with "Solved: every word fits a dictionary word" and the text reads NORTHERN LIGHTS DANCE ACROSS THE DARK SKY ON COLD AND QUIET NIGHTS. Notice the clues it had to work with: ISJDXV and USJDXV share their last five letters, which suits pairs like LIGHTS and NIGHTS, and the long word UQYXDRYU starts and ends with the same letter and repeats another in the third and seventh spots. Very few words have that shape.
When more than one answer fits
Short texts can have more than one key that fits. Try this one:
H JQQF ZAEEIR XRHKDRV ZHXSRUKR, HUF ZHXSRUKR PHWRV RMRYG DHYF ZYQTIRP H ISXXIR RHVSRY.
Auto solve reads it as A WOOD PUZZLE TEACHES PATIENCE, and under that it says "2 other readings also fit every word", offering FOOD and GOOD in place of WOOD. Every key fits the dictionary, so only sense can choose. Press Use this beside the GOOD reading and the key switches over. Lock code letter J (which now stands for G) to keep it if you run Auto solve again.
When a name is in the way
Names often aren't in the dictionary. In a test quote about Wayne Gretzky, the solver decoded SCORED MANY GOALS FOR THE EDMONTON TEAM DURING HIS LONG CAREER and left blanks in WAYNE and GRETZKY. From there, the missing letters are easy to fill in by hand.
Tips for solving cryptograms by hand
- Start with one letter words. A coded word of one letter is almost always A or I.
- Look for THE and AND. A three letter code word that turns up several times is very often THE. Once you have T, H and E, words like THAT and THEN fall into place.
- Use apostrophes. A single letter after an apostrophe is usually S, T, D or M. Two letters after one are often LL, RE or VE.
- Check doubled letters. Common doubles include LL, EE, SS, OO, TT and FF. A code word with a double in the middle is a strong clue.
- Use the letter counts carefully. In long passages the most common code letter is often E, but short quotes break that rule a lot.
- Check the rules of your puzzle. Some puzzles promise that no letter stands for itself. The solver assumes this by default. If your puzzle doesn't say so and the result looks off, untick "No letter stands for itself" and try again.
More solvers
If your puzzle is a word with some letters showing and the rest hidden, the hangman solver lists the words that fit. For scrambled words rather than coded ones, use the Jumble solver, and for a pile of letters you want to turn into every possible word, try the anagram solver.