Word Ladder
Transform words one letter at a time
Word Ladder (also called Doublets, invented by Lewis Carroll in 1877) is a word transformation puzzle where you change one letter at a time to turn a starting word into a target word. Each step must produce a valid English word. The challenge combines vocabulary knowledge with strategic thinking — you need to find a path through word-space that connects two endpoints, and shorter paths score better.
History & Origins
Word Ladders were invented in 1877 by Lewis Carroll, the author of Alice's Adventures in Wonderland. He called them "Doublets" and published them as a regular feature in Vanity Fair magazine. Carroll challenged readers to transform one word into another in the fewest steps possible — for example, turning HEAD into TAIL. The puzzle format has endured for nearly 150 years and is now studied in computer science as a classic graph theory problem, where words are nodes and single-letter changes are edges.
How to Play Word Ladder
Start & Target
You're given a starting word and a target word of the same length. Your goal is to transform one into the other.
One Letter at a Time
Each step, you change exactly one letter in the current word to create a new valid English word.
Valid Words Only
Every intermediate step must be a real English word. No abbreviations, proper nouns, or made-up words.
Same Word Length
All words in the chain must have the same number of letters. You cannot add or remove letters.
Fewer Steps = Better
Try to reach the target in as few steps as possible. The optimal solution uses the minimum number of transformations.
Think Ahead
Don't just change the first differing letter. Consider which intermediate words give you the most options for the next step.
Strategy & Solving Tips
Good Word Ladder solving combines vocabulary breadth with strategic path planning. These techniques help you find shorter, more elegant solutions.
- Work from both ends: try transforming the start word forward AND the target word backward, then meet in the middle
- Change vowels first — they tend to create more valid intermediate words than consonant changes
- Look for high-connectivity words (common patterns like _AT, _OT, _AN) as stepping stones
- Avoid rare or obscure words as intermediates — common words have more one-letter neighbors
- If stuck, try changing a letter you weren't planning to change. Sometimes indirect routes are shorter
- Build your vocabulary of short common words — knowing more 3 and 4-letter words opens more pathways
Word Ladder FAQ
Who invented Word Ladders?
Lewis Carroll (author of Alice in Wonderland) invented the puzzle in 1877, calling them "Doublets." The concept of transforming words one letter at a time has been a beloved puzzle format ever since.
Is there always a solution?
Not every pair of words can be connected. Some words are isolated in "word space" with no valid one-letter neighbors. Our puzzles are always guaranteed to have at least one valid solution.
How is the optimal solution determined?
The shortest path between two words can be found using graph theory (breadth-first search). Our puzzles show the minimum number of steps, though there may be multiple equally short solutions.
Can I change any letter position?
Yes! You can change any letter in the word at each step — first, last, or middle. The only rule is exactly one letter changes per step and the result is a valid word.
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Ready to Play Word Ladder?
Sharpen your vocabulary and strategic thinking with Word Ladder — the elegant puzzle of transforming words one letter at a time. Every step is a word, every chain is a journey.