Who invented the word ladder puzzle?

Lewis Carroll, who published the first set in Vanity Fair on 29 March 1877 and called them doublets. His own example turned HEAD into TAIL in five changes.

How long should a word ladder be?

The ladders here are dealt at par four, five or six changes, which is three to five words between the ends. Much shorter stops being a puzzle and much longer stops being fun to hold in your head.

Can two words have no ladder between them?

Very often. More than one in six common five-letter words has no neighbour at all, so nothing can be laddered to it. This game only ever deals pairs it has already found a route between.

Why was my word rejected when it is definitely a word?

Usually because it was not a legal move rather than not a word. Check that exactly one letter changed from the rung you are standing on, that the length matches, and that the word is not already on your ladder — repeats are refused, because any route that visits a word twice contains a shorter one that does not. The board names which of those it was.

Does taking a hint count against me?

Not against the solve. Hints are counted and shown in the closing panel, but they do not end the ladder, do not add a change, and do not stop a par finish being recorded as one. The only thing that costs you a change is actually typing the word the hint suggests.

How to Play Word Ladder

Change one letter of the start word to make another real word, then keep going until you reach the target. Letters never move position, every rung must be in the dictionary, and no word may be used twice. Par is the shortest route that exists; any longer route still solves the puzzle.

The rules, step by step

1Start at the word on the top rungEvery ladder opens with a start word and a target word of the same length, shown at the top and the bottom of the board.
2Change exactly one letterEach move replaces a single letter and leaves the others alone. Changing two at once is not a move, however good the resulting word is.
3Never move a letter's positionLetters stay in the slots they are in. You may not reorder them, add one or take one away — every rung is the same length as the last.
4Every rung must be a real wordEach step has to land on a word in the dictionary. The full ENABLE list is accepted, so a rare but genuine word is a legal rung and will be taken.
5No word twice on one ladderA rung already used is refused. Any route that revisits a word contains a shorter route that does not, so a repeat can never help you.
6Reach the target word to finishThe ladder ends the moment you land on the word at the bottom, whether that took par changes or twice as many.

Try it — the rules above, running

Par0Changes0Time0:00Streak0Ladder—

Hint writes the next word on a shortest route into the answer box — recomputed from the rung you are actually standing on, not from the route the puzzle had in mind, so it still helps after you have wandered; Undo takes the top rung back off, and Backspace on an empty box does the same. The three-dot menu holds today’s shared ladder, the word length, a reset to the start word, and a route revealed in full when you have had enough. Par is the shortest route through the common word list — a rarer word can beat it.

Your statistics · 4 letters

Played: 0
Won: 0
Win rate: 0%
Streak: 0
Best streak: 0
Best time: —
Fewest changes: —

This length

1,967 common four-letter words at 7.2 neighbours each — the classic size. Long enough that the route matters, short enough that changing the vowel is usually available.

Keyboard

A – Z: Type the next rung
Enter: Climb to it
Backspace: On an empty box, take the last rung back
Esc: Clear the box
Shift + F: Full screen
?: Show the shortcuts

What are the rules of a word ladder?

Start and target are the same length, and every rung between them is too.
One letter changes per step. Two is not a move.
Letters keep their positions — no reordering, no adding, no dropping.
Every rung must be a real word in the dictionary.
No word may appear twice on the same ladder.
Reaching the target finishes it, at par length or any longer.

How do you climb a ladder step by step?

1Read both ends firstTake COLD to WARM. All four positions disagree, so four changes is the floor — no route can be shorter, whatever you do. Par is four, which means the ideal route exists: every single move can land a letter in its final place, and none is wasted. When par is higher than that count, some position has to be visited twice.
2Take the change that opens the most doorsCOLD → CORD changes the third letter and lands on a word with eleven neighbours — ten of them new, since COLD itself is now spent. CARD, CURD and CORE are among them, and so are FORD, LORD and WORD down the _ORD family. Ten ways on is what a good rung looks like. COLD → COLA is just as legal and leaves three, which is what a bad one looks like.
3Aim at the target's neighboursWARM has exactly ten neighbours — FARM, HARM, WARD, WARE, WARN, WARP, WARS, WART, WARY and WORM. Any one of them is a win, so aim at the set rather than at WARM itself. CARD is one change from WARD, and WARD is one from WARM: COLD → CORD → CARD → WARD → WARM.
4Undo the moment a branch dries upIf a rung offers no new word that moves a letter into place, step back. The board's undo costs nothing and the step count only rises while you are on the board.

What should you do when you are stuck?

Take the hint. It is not a canned answer: it searches outwards from the rung you are standing on and names the next word on a shortest route from there, so it stays useful after you have wandered a long way off the generator's own route. If every word one letter away is already on your ladder, it says so and you undo instead. Failing that, switch the length — a three-letter ladder averages 12.8 ways out of every word, against 3.1 on five letters.

Why does the game accept a word it would never use itself?

Two lists are at work, and knowing which is which explains almost every surprise. The start word, the target and anything the hint offers come from a 25,000-word list of words a general audience actually knows, because a ladder whose middle rung is ZOEAE is a dictionary lookup rather than a puzzle. What you type is judged against the full 172,823-word ENABLE list instead.

Accepted: any lowercase entry in ENABLE, however obscure. QATS and AAHED are both legal rungs, and neither is in the shorter list, so neither will ever be dealt to you as a target.
Not in the list: proper nouns, abbreviations, anything hyphenated and anything with an apostrophe. ENABLE holds none of them, so none of them can be a rung.
Not a move, whatever the word: two letters changed at once, a different length, or a word already standing on your ladder. The board says which of the three it was rather than blaming your vocabulary.

That split is also why par is beatable. Par is the shortest route through the 25,000-word list, so a player who climbs through something rarer can come in under it, and the closing panel says so instead of quietly clamping the number.

How do you win more often?

Count the letters that already agreePositions where the start and target already match need no change at all, and every position that differs needs at least one. That count is a lower bound on par, and comparing it with the par shown tells you whether the route is direct or has to go round something.
Change the vowel before the consonantsThe vowel slot is where the graph is densest: BAT reaches BET, BIT, BOT and BUT without touching anything else. Swapping a consonant on a five-letter word often has only one or two options, and picking the wrong one costs two moves to undo.
Steer through the hub wordsA few words are joined to everything. CARE has 25 four-letter neighbours and PAT has 28 three-letter ones, so a route that passes through the _ARE or _AT family almost always has a next move waiting. A rung with one neighbour is the opposite: it commits you to a single continuation before you have seen where it goes.
Search from the target as well as the startAsk what could come immediately before the target — usually only a handful of words — and aim for those instead of the target itself. It converts a long forward search into two short ones, and on a five-letter ladder it is often the only practical way through.
On five letters, treat a dead end as information539 of the 3,050 common five-letter words have no neighbours at all, and many more have only one. If a promising rung offers nothing new, undo it immediately rather than hunting: the branch is genuinely finished, not merely difficult.

Common questions about word ladder

Who invented the word ladder puzzle?: Lewis Carroll, who published the first set in Vanity Fair on 29 March 1877 and called them doublets. His own example turned HEAD into TAIL in five changes.
How long should a word ladder be?: The ladders here are dealt at par four, five or six changes, which is three to five words between the ends. Much shorter stops being a puzzle and much longer stops being fun to hold in your head.
Can two words have no ladder between them?: Very often. More than one in six common five-letter words has no neighbour at all, so nothing can be laddered to it. This game only ever deals pairs it has already found a route between.
Why was my word rejected when it is definitely a word?: Usually because it was not a legal move rather than not a word. Check that exactly one letter changed from the rung you are standing on, that the length matches, and that the word is not already on your ladder — repeats are refused, because any route that visits a word twice contains a shorter one that does not. The board names which of those it was.
Does taking a hint count against me?: Not against the solve. Hints are counted and shown in the closing panel, but they do not end the ladder, do not add a change, and do not stop a par finish being recorded as one. The only thing that costs you a change is actually typing the word the hint suggests.

Ready to stop reading? Play word ladder on the full board, with controls and statistics tailored to that game.