Cryptarithm Solver

How to use the Cryptarithm Solver

1. Type your puzzle — words of letters, + between addends, = before the result. The classic is pre-loaded.
2. Hit Solve (or Enter). Classic puzzles crack in milliseconds.
3. Read the mapping chips, then check the aligned arithmetic — the solver re-adds the numbers itself and stamps the result verified.

Solving by hand: the column method

Work right to left, exactly like long addition. In SEND + MORE = MONEY, the units column gives D + E = Y + 10·carry. Since M is a leading letter of a 5-digit sum of two 4-digit numbers, M must be 1 — the carry out of the thousands column. Each column you solve pins down letters or kills whole branches: that pruning is why the solver finishes in milliseconds instead of trying all 10! mappings. When you're stuck on paper, chase the leading letters first — they carry the tightest constraints.

Famous puzzles to try

Beyond the Dudeney classic: CROSS + ROADS = DANGER, DONALD + GERALD = ROBERT (a touch harder — 10 distinct letters, expect a short wait), and TWO + TWO = FOUR. Puzzles with 9–10 distinct letters trigger a heads-up because the search space balloons; the solver caps itself at 8 seconds and tells you if it stopped early rather than hanging your tab.

What is a cryptarithm?

A cryptarithm (also called an alphametic) is a math puzzle where digits are replaced by letters — each letter stands for one digit, and different letters stand for different digits. The classic is SEND + MORE = MONEY: find the digit each letter hides so the addition is correct.

What rules does the solver follow?

Three rules, exactly as puzzlers use them: each letter maps to a single digit 0–9; different letters get different digits; and no word may start with zero — a leading letter can't be 0, or the word would have fewer digits than it shows.

How does the solver crack the puzzle?

It works column by column from right to left, like long addition. In each column it tries the still-unassigned letters that appear there, and immediately discards any combination that breaks the column's sum, carry included. That pruning cuts the search from billions of blind guesses to a fraction of a second for classic puzzles.

What if there is no solution?

The solver says so plainly: no solution — those words can't add up under the rules. Contradictory puzzles (like AB = BA, which would force A = B) are settled in milliseconds.

What if there are many solutions?

Some puzzles have more than one valid mapping. The solver collects up to 25 solutions and shows you the first, along with the count — so you can see how many exist.

Why the warning about 9 or 10 different letters?

Ten digits means up to 10! (about 3.6 million) possible mappings in the worst case. Column pruning usually tames it, but puzzles with 9–10 distinct letters can take seconds, so the search is capped at 8 seconds and the solver says so if it had to stop early.

Is my input sent anywhere?

No. Parsing and solving happen entirely in your browser with JavaScript. Nothing is uploaded, stored, or tracked.