A word ladder puzzle asks you to turn one word into another by changing one letter at a time, making a real word at every step. For example, CAT becomes DOG in three steps: CAT, COT, DOT, DOG. The aim is to reach the end word in as few steps as possible, or in exactly the number of steps given.
The rules
- The start and end words have the same number of letters.
- Each step changes exactly one letter. You cannot add, remove or swap the order of letters.
- Every step must be a real word. Names and abbreviations are usually not allowed.
- The shortest ladder wins, or you must match the number of steps the puzzle gives.
A little history
Word ladders were invented by Lewis Carroll, the author of Alice’s Adventures in Wonderland. He called them Doublets and published them as puzzles in the magazine Vanity Fair in 1879. His best-known example turns HEAD into TAIL:
HEAD → HEAL → TEAL → TELL → TALL → TAIL
The puzzle has had many names since, including word links, word golf and laddergrams, and it is still a favourite in puzzle books, classrooms and daily puzzle apps.
Examples to try
Try each one before you read the answer. The numbers are the steps in the shortest ladder we found using everyday words.
| Puzzle | Steps | One answer |
|---|---|---|
| CAT to DOG | 3 | CAT, COT, DOT, DOG |
| LEAD to GOLD | 3 | LEAD, LOAD, GOAD, GOLD |
| MILK to WINE | 3 | MILK, MILE, MINE, WINE |
| HATE to LOVE | 3 | HATE, HAVE, HOVE, LOVE |
| COLD to WARM | 4 | COLD, CORD, WORD, WARD, WARM |
| WET to DRY | 5 | WET, BET, BAT, BAY, DAY, DRY |
| APE to MAN | 5 | APE, APT, OPT, OAT, MAT, MAN |
Other ladders of the same length often exist. Check any pair, or ask for a new puzzle, with the word ladder solver and game, which always finds a shortest ladder and prefers everyday words.
Tips for solving word ladders
1. Change vowels first
Vowels are the most flexible letters. Swapping the vowel in CAT gives COT, CUT and CIT, while swapping a consonant often gives fewer real words.
2. Fix the letters that already match
Compare the start and end words letter by letter. Any letter that is already right can usually stay put, so focus on the ones that need to change.
3. Work backwards
Write down words one step away from the end word. Sometimes the last step is much easier to see than the first, and you can meet in the middle.
4. Use a stepping-stone letter
If you cannot change a letter directly, change a different letter first to create a word that allows it. In COLD to WARM, the O cannot become A straight away (CALD is not an everyday word), so the ladder goes through CORD and WORD first.
Worked example: COLD to WARM
- Compare the words: C/W, O/A, L/R and D/M all need to change, so the ladder needs at least four steps.
- Work backwards from WARM: one step away are WARD, WART, WORM, FARM and HARM, among others.
- From COLD, CORD changes L to R, a letter WARM needs.
- CORD to WORD changes C to W, another letter WARM needs.
- WORD to WARD fixes the vowel, and WARD to WARM finishes: COLD, CORD, WORD, WARD, WARM. Every step changed a letter towards the target, so four steps is the shortest possible.
5. Avoid dead ends
Some words, especially ones with unusual letter combinations, have very few neighbours. If you reach one, back up a step rather than pushing on.
Making your own word ladders
Pick two words of the same length with a link, such as opposites (HOT and COLD) or a transformation (SEED to TREE), then find a ladder between them. Four-letter words work best: there are plenty of them, and ladders are rarely more than six or seven steps. Check your puzzle with the solver so you can give the minimum number of steps.
Variations to try
- Fixed-length ladders: the setter gives the number of steps, and you must hit it exactly. This is the usual newspaper format.
- Longer words: five-letter ladders are much harder, because each word has fewer neighbours. FLOUR to BREAD takes six steps: FLOUR, FLOOR, FLOOD, BLOOD, BROOD, BROAD, BREAD. Try BLACK to WHITE before you check it in the solver.
- Themed ladders: every word on the ladder must be, say, an animal or a verb. These make good challenges for strong players.
- Racing: two players race to finish the same ladder, or take turns adding a rung, and the player who cannot move loses.
- Word golf: each step is a stroke, and the lowest score over a round of nine ladders wins.
Word ladders in the classroom
Word ladders are a popular spelling and phonics activity because each step practises one sound change. For younger children, use three-letter words and give a clue for each rung, such as “change one letter to make an animal”. For older pupils, set a target number of steps and award a bonus for beating it.
Questions and answers
What is a word ladder puzzle?
A word ladder turns one word into another by changing one letter at a time, with a real word at every step, such as CAT, COT, DOT, DOG.
Who invented word ladders?
Lewis Carroll invented them in 1879 and called them Doublets. His famous example turns HEAD into TAIL.
Can you add or remove letters in a word ladder?
Not in the classic puzzle. Each step changes exactly one letter, and the words stay the same length.
What is the best tip for word ladders?
Change vowels first and work backwards from the end word when you are stuck.