Word Puzzle Solver
Word Ladder Solver
Find the shortest path between any two words, changing one letter at a time. Mixed step counts, post-solve filters, and three dictionaries — including the same word list as Weaver.
Mixed results are enabled by default.
The solver now mixes different step counts together instead of filling the whole list with only one step length first. Manual answer caps like 12 or 18 are supported.
Our Word List uses the same local word lists as Weaver for 3 to 12 letter words.
Lewis Carroll Invented Word Ladders in 1879
In December 1879, the mathematician and author Charles Dodgson — better known by his pen name Lewis Carroll — published a new word puzzle in Vanity Fair magazine. He called it "Doublets." The rules were simple: transform one word into another by changing one letter at a time, and every intermediate step had to be a real word.
Carroll's original puzzle asked readers to turn HEAD into TAIL. The solution takes 5 steps: HEAD → HEAL → TEAL → TELL → TALL → TAIL. Turns out, HEAD → TAIL is one of the most famous word ladders ever — and it's still hard to beat. Carroll published dozens of Doublets in Vanity Fair throughout 1879 and 1880, and readers sent in their own. The puzzle caught on fast.
The name "word ladder" came later. Carroll's Doublets required each step to relate to the words' meanings — he insisted that HEAD and TAIL were thematically linked — but modern word ladders dropped that constraint. Today, any pair of equal-length words is fair game, and the only rule is that every step must be a valid word in whatever dictionary you are using.
The original HEAD → TAIL ladder in 5 steps
Why Some Word Pairs Have No Solution
Not every word pair has a ladder connecting them. The most common reason is a dead end: you change a letter, land on a valid word, and then find that every possible next change produces nonsense. If every path from that word hits a dead end, the ladder is unsolvable.
Take BRICK → STONE. All five letters differ, which means every position needs to change at least once. The problem is that intermediate words like BRACE, TRACK, or STOCK exist — but they do not form a connected chain that reaches STONE. In the OWL2 dictionary, BRICK → STONE simply has no solution.
Dictionary gaps cause most failures. SOWPODS contains roughly 267,000 words while OWL2 has about 187,000. Those extra 80,000 words in SOWPODS include obscure terms that can bridge steps where OWL2 hits a wall. A pair that fails in OWL2 might solve cleanly in SOWPODS. If your ladder comes back empty, switch dictionaries and try again.
This won't find paths using words outside the selected dictionary. If neither dictionary contains a bridging word, the pair is genuinely unsolvable by the rules of the game.
How Our Solver Finds Every Possible Path
The solver uses breadth-first search (BFS). BFS explores all 1-step words from the start word before any 2-step words, all 2-step words before any 3-step words, and so on. Because of this layer-by-layer approach, the first complete path BFS discovers from start to end is always the shortest possible path. No exceptions.
For longer ladders, the solver also runs bidirectional search — it explores outward from both the start word and the end word at the same time. When the two frontiers meet, a path exists. Bidirectional search cuts the search space roughly in half compared to one-directional BFS, which makes a real difference on 7+ letter words where the word graph is large.
Once the shortest paths are found, the solver keeps going in mixed mode. It continues the BFS to discover paths that take one more step, then two more steps, filling the result set with ladders of different lengths until it hits the answer cap you set. This is why you might see 23 shortest paths and 24 with extra steps — same start and end words, different routes.
Every path the solver returns is valid. It never skips a word, never reuses a word in the same ladder, and never produces a step that is not in the chosen dictionary. If the solver says a path exists, you can verify it one step at a time.
Three Dictionaries, Three Different Results
The dictionary you pick changes which words count as valid steps, and that changes which ladders exist. Here is how the three options differ:
Our Word List
Uses the same word sets as the daily game Weaver for 3–12 letter words. If a ladder works in Weaver, it works here with the same step count. This is the default because it matches the most popular word ladder game online.
OWL2 (US Scrabble)
The official Tournament Word List used in North American Scrabble. About 187,000 words. Smaller than SOWPODS, so some ladders that exist in international play will not appear here. Good if you want widely-accepted words only.
SOWPODS (World)
Combines OWL2 with the international Scrabble list, totaling roughly 267,000 words. Adds UK-specific terms, Commonwealth English, and older tournament words. The largest dictionary — best chance of finding a solution when OWL2 comes up empty.
A concrete example: COLD → WARM has a 4-step ladder in all three dictionaries. But COLD → FARM might need 5 steps in OWL2 and only 4 in SOWPODS because SOWPODS contains a bridging word that OWL2 does not recognize. The dictionary is not a minor setting — it determines what counts as a valid step.
When Mixed Step Counts Reveal Better Paths
The shortest ladder between two words is not always the most interesting one. Consider COLD → WARM. The 4-step shortest path might go through CARD. A 5-step path might go through CORD → WORD → WARD → WARM — a route that strings together common, recognizable words instead of scraping by with obscure ones.
Mixed mode finds the shortest paths first, then continues the search to collect longer paths that use different intermediate words. The result is a combined set — you might get 23 shortest paths and 24 with extra steps in a single solve. The step-count filter at the top of the results lets you isolate any step length you want.
This matters if you are solving word ladders for a game like Weaver. Weaver requires the shortest possible path, so you need to confirm the minimum step count first. But if you are exploring word ladders for fun or education, the longer paths often travel through more common words and are easier to follow by hand.
The answer cap controls how many total paths the solver returns. Start with 10 to see a sample, then raise it to 50 or 100 if you want to explore more routes. The solver stops when it hits the cap or exhausts all paths — whichever comes first.
Tips for Solving Word Ladders by Hand
Work from both ends
Write the start word at the top of the page and the end word at the bottom. Change one letter from each end and see if the middle words can meet. This halves the effective search space because you are building two short ladders instead of one long one.
Focus on letters that differ
If HEAD and TAIL differ in positions 1, 2, 3, and 4, you need to change all four positions. Do not waste steps changing a letter back to something it already was. Track which positions still need to flip and prioritize those.
Use rhyming word families
If you need to change the first letter of a word ending in -AIL, run through the family: BAIL, FAIL, HAIL, JAIL, MAIL, NAIL, PAIL, RAIL, SAIL, TAIL. Rhyming families are the fastest way to brainstorm valid intermediate words because your brain already groups them.
Accept detours
Sometimes you need to change a letter to something wrong temporarily so you can change another position. HEAD → HEAL changes the 4th letter to L, which then lets you reach TEAL → TELL → TALL. Without that detour through HEAL, you cannot get the L into position 4. Detours are not wasted steps — they are how most ladders actually work.
Verify each step out loud
It is embarrassingly easy to write down a word that looks real but is not. SHOAL is a word. SHOEL is not. Say each intermediate word out loud — if you cannot find it in a sentence, it probably is not valid. When in doubt, check it against the dictionary you are using.
Word Ladder Solver FAQ
What is a word ladder?
A word ladder transforms one word into another by changing exactly one letter at a time, and each intermediate step must be a valid word. Lewis Carroll invented the puzzle in 1879 under the name "Doublets." The classic example turns HEAD into TAIL in 5 steps: HEAD → HEAL → TEAL → TELL → TALL → TAIL.
Why does my word pair have no solution?
Most unsolvable pairs hit a dead end because no valid word in the dictionary bridges two consecutive steps. BRICK → STONE, for instance, requires changing 5 of 5 letters, and the intermediate words simply do not exist in standard dictionaries. Try switching to a larger dictionary like SOWPODS, which includes more obscure words that might create a path.
What is the difference between the three dictionaries?
Our Word List uses the same word sets as the game Weaver for 3–12 letter words. OWL2 is the official US Scrabble dictionary — smaller but widely accepted. SOWPODS combines OWL2 with the international Scrabble list, adding thousands of words valid in UK and Commonwealth play. A pair that has no solution in OWL2 might have one in SOWPODS.
Why does the solver return paths with different step counts?
Mixed mode finds the shortest paths first, then continues searching for longer paths that use different words. The shortest path from COLD to WARM takes 4 steps, but a 5-step path might travel through words like WORD and FARM that the 4-step path skips. Mixed mode shows you both, so you can pick the route you find most interesting.
How do I filter results after solving?
Two post-solve filters are available. The step-count buttons at the top of the results show only paths with that exact number of steps. The word search box lets you type any word — only paths containing that word appear. Combine both filters to narrow things down fast.
Does the solver guarantee the shortest possible ladder?
Yes. The solver uses breadth-first search, which explores all 1-step paths before any 2-step paths, all 2-step paths before any 3-step paths, and so on. The first complete path it finds is always the shortest. If no path exists in the chosen dictionary, it tells you so.
Can I solve ladders longer than 4-letter words?
Yes. Our Word List supports 3 to 12 letter words. OWL2 and SOWPODS support even longer words. Longer words have more letter positions to change, which means more potential intermediate words — but also more ways to hit dead ends. Try WELCOME → GOODBYE for a real challenge.