What is a Word Ladder?
A word ladder is a puzzle in which you turn one word into another by changing a single letter at a time, and every word along the way has to be a real word. Lewis Carroll invented it in 1877 to entertain two bored children. It has not needed improving since.
The definition
A word ladder (also called a doublet, word chain, word morph, word golf or just the change-one-letter game) links a start word to a target word through a chain of intermediate words. Each word in the chain differs from the one before it by exactly one letter, and every word, including the ones in the middle, must be in the dictionary.
The example everyone learns first is CAT to DOG:
CAT → COT → COG → DOG
Three steps: A becomes O, T becomes G, C becomes D. Three real words along the way. That is a valid word ladder, and three is the fewest steps that will do it.
Lewis Carroll's Doublets
Carroll (Charles Lutwidge Dodgson, the Oxford mathematician who wrote Alice's Adventures in Wonderland) was staying with friends on Christmas Day 1877 when two girls, Julia and Ethel Arnold, complained that they had nothing to do. He made up the puzzle on the spot.
He called it Doublets. From 29 March 1879 it ran as a column in Vanity Fair, with readers sending in their chains and a prize for the shortest, and later that year the puzzles were collected into a small book, Doublets: A Word-Puzzle. His rules were short: the two words must be the same length, each link may change only one letter, and the letters may not be rearranged. Those are still the rules.
The example he used to explain it was HEAD to TAIL:
HEAD → HEAL → TEAL → TELL → TALL → TAIL
Five steps. He went on to set APE to MAN, FLOUR to BREAD and BLACK to WHITE, which is still a hard one.
The rules in plain English
- You have two words of the same length: a start word and a target word.
- Change exactly one letter of the current word to make a new word.
- The new word has to be a real word, one that is in whatever dictionary you have agreed on.
- No rearranging, no adding, no removing. The length stays fixed.
- Repeat until you reach the target.
- Fewer steps is better. The shortest chain that exists is the optimal solution.
Worked examples
COLD to WARM
COLD → CORD → WORD → WARD → WARM
Four steps, and the first one is the odd one: CORD moves away from WARM before anything moves toward it. After WORD only the vowel and the last letter are wrong, and WARD fixes the vowel.
FLOUR to BREAD (Carroll's)
FLOUR → FLOOR → FLOOD → BLOOD → BROOD → BROAD → BREAD
Six steps. The whole ladder hangs on the double O: FLOOR to FLOOD is the pivot, and BLOOD and BROOD carry it across.
APE to MAN (Carroll's)
APE → APT → OPT → OAT → MAT → MAN
Five steps. Carroll was setting this in 1879, twenty years after On the Origin of Species, and he knew exactly what he was doing with it.
FISH to BIRD
FISH → FIST → GIST → GIRT → GIRD → BIRD
Five steps. GIRT and GIRD are the kind of words nobody says and every word-ladder player knows. The middle of a hard ladder is usually made of them.
Why some words are easy and others are walls
CAT has sixteen one-letter neighbours: BAT, EAT, HAT, MAT, OAT, PAT, RAT, SAT, VAT, COT, CUT, CAB, CAN, CAP, CAR and CAW. From CAT you can go almost anywhere. A word with an awkward consonant cluster might have one neighbour, or none. Words with many neighbours are the stepping stones; words with few are the corners of the puzzle, and the step into or out of one is where most ladders are won or lost.
What makes it hard
The rules fit on a line and the puzzle still beats people, for three reasons.
- Vocabulary. The chain usually runs through words you know but never use (CORD, GIRT, BROOD), and recognising a word on a page is not the same as producing it on demand.
- Planning. Every move opens some doors and closes others. You cannot see the whole path from the start, so you plan two steps ahead and keep a way back.
- Pattern sight. Noticing that TWO and TOO are a letter apart, or that HOME and HONE share three, gets faster with practice. It is a skill, and it is the skill the game trains.
Word ladders beside other word puzzles
| Puzzle | Mechanic | Famous example |
|---|---|---|
| Word ladder | Change one letter at a time, all valid words | HEAD → TAIL |
| Wordle | Guess a hidden word from coloured clues | 5-letter daily |
| Anagram | Rearrange letters into a new word | LISTEN ↔ SILENT |
| Crossword | Fill a grid using clues | NYT crossword |
| Spelling Bee | Form words from a fixed set of letters | NYT Spelling Bee |
| Weaver | 4-letter daily word ladder | 4-letter daily |
Nothing is hidden in a word ladder. You see both ends from the first second; the whole job is the path between them. That is the difference from Wordle, and it is why the two games feel nothing alike.
How Word Labyrinth plays it
Word Labyrinth is our free word ladder game for the web, iOS and Android. The name is the point: from any word a dozen one-letter edits branch off, most of them dead ends, and finding the short path through feels like a maze. We allow one thing Carroll did not: a step may also add a letter, so the target can be longer than the start. Puzzle 4 on 5 October 2026 was LACK to SOLAR:
LACK → SACK → SOCK → SOAK → SOAR → SOLAR
Four swaps and one added letter. Each day there are 5 ranked puzzles, from a two- or three-step opener to a hard one of up to seven steps, plus a leaderboard, streaks, an Expert mode of 8-step-and-up puzzles, and the same again in ten more languages, eleven in all.
Play a word ladder right now
5 fresh daily puzzles. Free. No sign-up required to play.
Play Word Labyrinth