Word Ladder
A word ladder links two words of the same length through a chain of real words, swapping just one letter each time – COLD can climb to WARM, for example. This free tool both solves ladders and gives you new ones to play.
Opens Unscramble Words 4U, our free word-puzzle site, in a new tab. Free, with no sign-up.
What it does
The tool has two modes. Solve a ladder takes a start word and an end word, each up to eight letters and both the same length, and finds the shortest possible chain between them. It works outwards ring by ring – all words one change away, then those two changes away, and so on – until the goal appears, favoring everyday words and using rarer ones only when it has to. The letter that changes on each rung is highlighted.
Play mode gives you a puzzle: two common words of three, four or five letters plus how many moves the shortest route takes. You type each next rung yourself, and every entry has to be a genuine word one letter different from the one before. The puzzle type is usually credited to Lewis Carroll, who published it as Doublets in 1879. It’s great for spelling, phonics and vocabulary.
How to use it
- To solve, choose Solve a ladder, type the start word in From and the goal in To, then press Find the ladder.
- Read down the result – the highlighted letter on each line shows what changed.
- To play, choose Play, pick a word length of 3, 4 or 5, and press New puzzle.
- Type your next word and press Add. It must be real and differ by exactly one letter from the previous rung.
- Took a wrong turn? Undo takes back your last step. Show me completes the remaining rungs for you.
More tips
- If you’re stuck going forward, work back from the end word; the last few rungs can be easier to spot.
- Longer words have fewer one-letter neighbors, so ladders between them are rarer and sometimes impossible.
Ideas for the classroom and homeschool
- Grades K–2Build a three-letter ladder together on the board, such as CAT to DOG, sounding out each new word. It fits naturally with phonics and blending.
- Grades 3–5Give partners a four-letter puzzle from Play mode and see who matches the shortest step count. Use Show me only after everyone has tried.
- Grades 4–8Students invent their own start and end words, test them in the solver, and trade with a partner – noting which pairs can’t be joined at all.
- Grades 6–8Connect to computer science: discuss how searching one step out, then two, guarantees the shortest route, and compare that with how students search by hand.
Questions
Can I add or drop letters?
No. In a traditional ladder the length stays fixed, and each rung swaps exactly one letter.
Why can’t it join my two words?
A few words have no one-letter neighbors at all, or sit in a cluster that never links to the other word. Pick a different start or end.
How long can the words be?
The solver accepts up to eight letters. Play mode offers three, four or five.
Who came up with word ladders?
They are generally credited to Lewis Carroll, the author of the Alice books, who called them Doublets. Sharing one of his puzzles can make a nice link to an ELA unit.
Opens Unscramble Words 4U, our free word-puzzle site, in a new tab. Free, with no sign-up.