How the Scrabble Best Move Finder Works

After reading this you will understand how a Scrabble engine searches every legal placement on a board, how each move is scored to the point, and how to read the ranked list so you pick the play that actually wins the game.

What the finder does, with one example

Give the tool three things: the tiles already on the 15×15 board, your seven-tile rack, and a language. It returns the twenty highest-scoring legal moves, each with its exact score and board position. Click a row and the placement is drawn so you can see where every tile lands.

Here is the hook. Suppose the only word on the board is HELLO played through the center, and your rack is QUIZZED (using one blank for the second Z). A human eyes the triple-word square and hopes. The finder tests every anchor square next to HELLO, every direction, and every arrangement of your rack that forms a valid word plus valid cross-words. It reports that hooking QUIZZED so the Q covers a double-letter square scores far more than the obvious short plays, and it tells you the number before you commit.

The point is not that the engine is clever. The point is that it is exhaustive. It never misses a legal play, and it scores each one exactly the way a tournament adjudicator would.

When to use it, and when not to

Use it to study. After a real game, rebuild a position where you were stuck and see what you missed. Use it to check a claim ("was there really a bingo there?"). Use it to set puzzles: pick a rack and board, then ask friends to find the play the engine ranks first.

Do not use it during a rated game against a human. That is cheating, and every serious club forbids it. Also treat the word list as a strong default, not gospel. English here is the ENABLE list of about 173,000 words. Your club may use TWL or SOWPODS, which differ by thousands of entries, so a move the finder loves might be challenged off the board in your room.

The dictionaries differ between apps and federations. If a move scores well here but your opponent challenges it, check your event's official list. The finder tells you the best play in its dictionary, not in every dictionary.

How a move is scored

Every score the finder shows is built from one formula. Let a play use tiles across one or more squares. The score of a single word formed is:

S = \left( \sum_{i} v_i \cdot m_i \right) \cdot W + B

Here v_i is the face value of the tile on square i, and m_i is its letter multiplier: 1 normally, 2 on a double-letter square, 3 on a triple-letter square. The multiplier W is the product of all word multipliers under newly placed tiles: a double-word square contributes a factor of 2, a triple-word square a factor of 3, and two double-word squares in one play give 2 \times 2 = 4. The bonus B is 50 if this play used all seven rack tiles, otherwise 0.

The rule that trips people up: a premium square counts only when a tile is placed on it this turn. Tiles already on the board score their face value with no multiplier. A blank always contributes v_i = 0, even sitting on a triple-letter square, because zero times anything is zero.

The total for the turn adds the main word plus every perpendicular cross-word your new tiles create. Each cross-word is scored with the same formula, and each must itself be a legal word or the whole play is illegal.

How the search finds every legal play

The engine does not shuffle your rack at random. It walks the board looking for anchor squares: empty squares next to an existing tile (on an empty board, the single anchor is the center star). Any legal play must touch the existing letters, so every play passes through at least one anchor.

At each anchor, for each direction, the search extends left into already-placed tiles, then grows rightward one tile at a time. It only follows a branch if the letters so far spell a valid prefix of some dictionary word. That prefix check is what makes the search fast. A rack of 7 tiles has up to 7! = 5040 orderings, but most orderings die at the first or second letter because no word starts that way.

For every candidate word, the finder also checks each cross-word your new tiles form. If any cross-word is not in the dictionary, the play is discarded. What survives is scored with the formula above, and the top twenty by score are kept.

The whole search runs in your browser. Your board and rack never leave your device. For Polish, words are capped at 9 letters (about 760,000 forms) so the search stays quick; that still covers any play using only your rack plus common hooks.

A worked example you can reproduce

Load the tool's demo (the button uses the field defaults) and follow the arithmetic by hand.

Scoring a bingo across a double-word square

Take a rack that plays out to a seven-tile word whose first tile lands on a double-word square, with no letter-premium tiles used, and tile values summing to 24 before multipliers.

Sum the face values of all seven placed tiles: 24. No letter square is covered, so every m_i = 1 and the letter sum stays 24.
One double-word square is covered, so W = 2. Multiply: 24 \times 2 = 48.
All seven rack tiles were used, so add the bingo bonus: 48 + 50 = 98.
Check cross-words. Suppose the play forms one two-letter cross-word worth 5 with no premium under the new tile. Add it: 98 + 5 = 103.

The finder reports 103 for this play and ranks it against the other nineteen. Every number here is one you can verify by counting tiles.

Reading and interpreting the results

The table is sorted by score, highest first. The top row is the highest-scoring legal play, but highest is not always best. Three things to weigh:

Leave. The tiles you keep matter. Scoring 30 by dumping your S and blank can be worse than scoring 26 and keeping them for a future bingo.

Board risk. The top play may open a triple-word square for your opponent. The finder scores only your turn; it does not model their reply.

Bingo hunting. If two plays are close, the one that keeps a balanced rack (a mix of common consonants and vowels) is usually the stronger practical choice.

The bingo bonus is the single largest block, which is why using all seven tiles dominates the ranking so often.

Common mistakes

Entering blanks wrong is the frequent one. A blank already on the board is a lowercase letter (the letter it stands for), and it scores zero. A blank on your rack is ?, and the finder chooses what it represents. If you type an uppercase letter for a board blank, the engine scores its full value and inflates every play through it.

Forgetting that premiums are one-time is the other. A triple-word square that already has a tile on it gives you nothing when you build off it. The multiplier fired on the turn that tile was placed and will never fire again.

Finally, on an empty board the first play must cross the center star, and that square doubles the word. The finder enforces this, so a first move it reports has already had the center double applied.

Related solvers on this site

If you like watching an exhaustive search explain itself, try the Wordle Solver & Explorer, which ranks next guesses by how much they cut the candidate list. For pure logic puzzles, the Sudoku Solver names the human technique behind each move, and the Nonogram Solver explains every deduced cell line by line.

Frequently asked questions

Does the finder pick the best strategic move or just the highest score?

The highest score. It ranks the top twenty legal plays by points for this turn only. It does not model your rack leave or your opponent's reply, so treat the top row as the point ceiling, not automatic advice.

How do I enter a blank tile?

Use ? for a blank on your rack and let the finder assign its letter. For a blank already on the board, type the lowercase letter it represents. Blanks always score zero points.

Why does my club reject a word the finder likes?

English here uses the ENABLE list of about 173,000 words. Clubs often use TWL or SOWPODS, which include or exclude different words. The finder is correct for its dictionary; check your event's official list.

Can it handle six languages with different tile values?

Yes. Each language uses its own official tile values and its own word list, from about 340,000 Danish forms up to about 790,000 Norwegian forms. Romanian is played without diacritics.

Does my board data get uploaded anywhere?

No. The search runs entirely in your browser. Your board, rack and results stay on your device.

Try it yourself in the tool