BIRD2WORD BETA

Swift Words, Sharp Minds.

What is BIRD2WORD?

BIRD2WORD is a word ladder game. You're given a start word and a target word, both four letters long. Your job is to turn one into the other by changing exactly one letter at a time — and every step along the way has to be a real word.

A quick example

To go from BIRD to WORD, one path looks like this:

Each word differs from the one before it by a single letter. That's the whole game — simple to learn, but the shortest path isn't always obvious.

How to play

• Type your guess. On desktop, just type on your keyboard. On a phone, tap the puzzle board and your keyboard will pop up.
• Press Enter to submit a word. If it's a real word and only one letter away from your last word, it gets added to your chain.
• Tile colors give you feedback: blue means that letter matches the target word, yellow means that's the letter you just changed.
• Backing up is easy — just retype a word you already used (or the start word) and your chain rewinds to that point, no penalty.

Modes

• Random by Difficulty — Easy, Medium, or Hard puzzles, pulled at random from a dictionary of nearly 5,000 four-letter words.
• Fun Word Pairs — a curated set of especially fun or clever start/target pairs.

The dictionary

BIRD2WORD's word list is built by merging three long-standing, freely licensed English word sources, rather than any single commercial dictionary:

• web2 — the word list drawn from Webster's Second International Dictionary, part of the Moby Word Lists compiled by Grady Ward and placed in the public domain, now also mirrored by Project Gutenberg.
• aspell american-english — the word list shipped with GNU Aspell, built from Kevin Atkinson's SCOWL (Spell Checking Oriented Word Lists) project, a free, permissively licensed collection that itself combines several public sources — including Moby Words, WordNet, and the ENABLE word list.
• ENABLE — "Enhanced North American Benchmark LExicon", a free, public-domain word list built specifically as a Scrabble-dictionary equivalent, merged in directly (not just inherited secondhand through SCOWL) for broader Scrabble-style word coverage.

We went with freely licensed, well-established lists like these instead of a single commercial dictionary so BIRD2WORD's word list can stay open. All three are merged, then filtered down to real, playable four-letter words — proper nouns, abbreviations, and offensive terms are excluded by hand.

On sourcing: the actual "Official Scrabble Players Dictionary" is copyrighted, commercially published content, so it isn't something we can legally reproduce here. ENABLE was built as a free, legally unencumbered substitute with comparable Scrabble-tournament word coverage, which is why it's the third source merged in above.

Flip It

Stuck, or just want a change of pace? Hit Flip It at any time to swap your start and target words. Nothing you've already solved is lost — the words you've used simply reappear on the board from the other end, already filled in. You just need to build a path until you connect to them. Flip as many times as you like.

Mercy

If you want to give up on a puzzle, hit Mercy! and confirm. The rest of the path will be filled in for you so you can see how it plays out. Give-ups don't count toward your stats or score — they're just there so you're never stuck.

Scoring

Your score rewards solving a puzzle in as few words as possible, and rewards speed too — though word-efficiency matters a lot more than time. Harder puzzles (ones with a longer shortest path) score higher. After you solve a puzzle, you can also tap "Shortest possible" in the results to reveal one example of the most efficient path.

Under the hood, every solve is scored out of a base of 10,000 points, adjusted by three factors multiplied together:

• Efficiency — (shortest possible words ÷ words you actually used), squared. This is the biggest factor by far: solving in the fewest possible words gives you a perfect 1.0 here, while every extra word shrinks it fast.
• Speed — 1 ÷ (1 + seconds ÷ 60). A gentle bonus for solving quickly that fades the longer you take, roughly halving for each extra minute or so.
• Difficulty — 1 + (shortest possible words − 2) × 0.1. Puzzles with a longer optimal path get a modestly higher ceiling, since they're more impressive to solve.

Those three factors are multiplied by the 10,000-point base and rounded to give your final score. Solving in the fewest possible words is always worth far more than solving fast, so don't rush at the expense of taking a longer path.

Stats

Your average and best time, word count, and score are tracked separately for each mode and difficulty, right in your browser. They stay on your device and aren't shared anywhere.

Playground

Want to build your own puzzle? Head to the Playground — type in any start and target word (4 or 5 letters) and it'll find the shortest ladder between them, if one exists.

Merch

Curious what BIRD2WORD word pairs might look like on a sticker or shirt? Check out the Merch preview — a first look at a few designs. Nothing's for sale yet.