Start with letter counts

Quick answer

To unscramble letters without guessing, count the letters you have, look for fixed patterns, try likely word lengths, and reject any word that uses letters you do not have.

A candidate word is only valid when every letter can be supplied by your input. This is why duplicate letters matter: one t cannot make a word with two t's.

Use patterns after the first pass

If a board gives you a starting letter, ending letter, or contained letter, apply that filter after the broad search.

Try Word Helper

Use the Word Unscramble tool for broad words-from-letters results, then scan by length.