Word Ladder Solver

How to Use the Word Ladder Solver

1. Enter the two words. They must be the same length, from two to ten letters. Press one of the examples to see how it looks.
2. Rule out words if you like. Type words to avoid, separated by spaces or commas. The solver will find a ladder that does not use them.
3. Read the ladder. Each row is one step; the letter that changed from the row above is highlighted. The cards show how many letters change, how many words the ladder has, and how many different shortest ladders exist.
4. Look at the alternatives. Other shortest ladders are listed underneath, in alphabetical order, so you can pick the one with the most familiar words.

What a Word Ladder Is

A word ladder turns one word into another by changing a single letter at a time, with a real word at every rung. The puzzle was devised by Lewis Carroll in 1877, who called it Doublets. A classic example turns HEAD into TAIL in five steps: head, heal, teal, tell, tall, tail. The rules here are the classic ones: every word has the same length, each step changes exactly one letter in place, and letters are never added, removed, or rearranged.

How the Solver Finds the Shortest Ladder

Two words are neighbors when they differ in exactly one position. To find neighbors without comparing every pair, the solver files each word under one wildcard key per position: cold goes under ?old, c?ld, co?d, and col?, and every word that shares a key is a neighbor. It then runs a breadth-first search outward from the start word, level by level, which guarantees that the first time it reaches the end word it has found the minimum number of steps.

To count and list every shortest ladder it also searches from the end word. A word sits on a shortest ladder exactly when its distance from the start plus its distance from the end equals the ladder length, so the alternatives are traced through those words only. That is why a count such as 17 or 14 appears instantly instead of after trying every route.

Worked Examples

Cold to warm takes four steps in six ways, and the first is cold, cord, card, ward, warm. Cat to dog has two: cat, cot, cog, dog and cat, cot, dot, dog. The classic pair behaves differently. Head to tail takes only four steps on this list, through heil, a rare verb. Put heil in the words to avoid and the answer becomes five steps with 17 ladders, one of which is the traditional route above.

When There Is No Ladder

Some pairs cannot be joined. Words with no one-letter neighbors, such as zebra, are islands, and the word list can split into groups that never meet. The solver then says how many words it could reach from the start. Ending a ladder with a word the list lacks is allowed — the page tells you when an end word is unlisted — but every word in between must come from the list, and words you chose to avoid are removed from it.

Solving a Ladder by Hand

• Work from both ends. List the neighbors of the start and the end and look for a word they share, or a short bridge between them.
• Change consonants first. Vowel changes often produce fewer real words.
• Keep common letters. Words ending in -ate, -ine, or -ore have many neighbors, so they make good stepping stones.
• Count the differences. If the words differ in four positions, the ladder needs at least four steps; a longer ladder means no direct path exists.

About the Word List

Steps are drawn from ENABLE, the public-domain list behind CitationEasy's Anagram Solver. It is generous, so shortest ladders often use rare words like wold or corm. Names, abbreviations, and capitalized words are not in it. If a ladder uses a word you or your class would not accept, add it to the words to avoid and the solver finds the next-best route.

Frequently Asked Questions

What are the rules of a word ladder?

Start with one word and finish with another of the same length. Each step changes exactly one letter, keeping the others in place, and every step must be a real word. You cannot add, remove, or rearrange letters, and the aim is the fewest steps.

Who invented the word ladder?

Lewis Carroll, the author of Alice's Adventures in Wonderland, devised it in 1877 and called it Doublets. He published puzzles in a magazine and later in a book. Teachers now use ladders to practice spelling, phonics, and vocabulary.

Is the ladder the solver gives always the shortest?

Yes, for the word list it uses. It searches level by level, so the first route to the end word has the fewest possible steps. A different dictionary can give a shorter or longer ladder, because a rare word might open a shortcut.

Why does the solver use words I do not know?

The list is built for word games and includes uncommon words, plurals, and verb forms. Add any word you do not want to the words to avoid and the solver will search around it. The new ladder may need more steps.

Can I use words of different lengths?

Not in a classic ladder. Both words must be the same length, because each step changes a letter in place. Variants that allow adding or removing a letter exist, but they are a different puzzle and this solver does not do them.

What if no ladder is found?

The two words are in separate groups, with no chain of one-letter changes between them in the word list. The page tells you how many words can be reached from the start word. Try a different pair, or remove some words from the avoid list.

Does it work on a phone?

Yes. The solver runs in your browser. The word list is downloaded once per visit, and your words are not sent anywhere.