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Word Ladder Solver

Find the shortest chain of real words from a start word to an end word, changing exactly one letter at each step, using breadth-first search over the dictionary.

Enter two real words of the same length. Each rung changes exactly one letter.

— output appears here —

About this tool

The Word Ladder Solver finds the shortest chain of real words that turns one word into another by changing a single letter at a time — the classic doublets puzzle invented by Lewis Carroll. Enter a start and end word of the same length (both must be real dictionary words) and the tool returns a shortest ladder, such as COLD → CORD → CARD → WARD → WARM, or tells you that no path exists.

Under the hood it treats every word of that length as a node in a graph, with an edge between any two words that differ in exactly one position. To search efficiently it groups words into wildcard buckets (for CORD it stores keys like *ORD, C*RD, CO*D and COR*) so neighbours are found by instant lookup, then runs a breadth-first search, which guarantees the fewest possible steps. The search is capped so it always returns quickly rather than hanging on hard cases.

All of this happens locally in your browser against a bundled public-domain English word list — nothing is uploaded. Because the ladder can only step through words that exist in that list, an otherwise valid chain will be reported as impossible if a needed intermediate word is missing; the list is public-domain, so some very modern or borrowed words may not be present.

Frequently asked questions

What is a word ladder?
A word ladder (or doublets puzzle) transforms one word into another by changing exactly one letter at a time, where every intermediate step must also be a real word of the same length. This tool finds the shortest such chain.
Do the two words have to be the same length?
Yes. Changing one letter never changes a word's length, so the start and end words must have the same number of letters, and both must exist in the dictionary. Lengths from 2 to 9 letters are supported.
Why does it say no path exists?
Either the two words genuinely cannot be linked, or a required intermediate word is not in the word list. Because only words present in the dictionary can be used as steps, a missing intermediate breaks the chain.
Is the ladder the shortest possible?
Yes. The solver uses breadth-first search, which always finds a path with the minimum number of steps. If several shortest ladders exist, it returns one of them; the step count shown is optimal.

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