Codeword Solver
A codeword is a crossword grid with no clues, where each square holds a number that stands for a letter. This free solver cracks the code from your grid and lets you decide how much help you want.
Opens Unscramble Words 4U, our free word-puzzle site, in a new tab. Free, with no sign-up.
What it does
In a codeword, each of the 26 letters hides behind its own number, and a given number stands for one letter throughout the grid. Two or three letters are usually handed to you up front. You copy the numbers into the solver, add those free letters, and it checks each horizontal and vertical entry against a word list until every number has a letter that works wherever it appears.
What makes it good for learning is that nothing is forced on you. You can uncover one letter, the entry you’ve highlighted, or the whole puzzle, and you can test your own guesses without seeing the solution. That suits stuck puzzlers and teachers who want students reasoning about letter patterns instead of copying answers. It all runs in the browser, so the grid isn’t uploaded anywhere.
How to use it
- Set the grid size to match your puzzle. Rows and columns each run from 5 to 19, and the tool opens at 13 × 13, a typical newspaper size.
- Select a square, then enter the number printed in it (phones get an on-screen pad). Shaded squares are entered as 0, # or the letter B. Use the arrow keys to get around; tapping a square twice flips between across and down.
- Have the puzzle as text? Use the paste box instead: each line of text is one row, with a space between numbers and # marking shaded squares.
- Add the letters the puzzle gives you for free, plus any you’ve already figured out, and press Solve.
- Now pick your help. Reveal one letter gives a single number away; Reveal the selected word completes just the highlighted entry; Reveal everything finishes the puzzle. Check my letters flags wrong guesses in red without showing anything else.
- Load an example demonstrates how it works, and Clear grid wipes the board.
More tips
- If the tool says the grid is only partly solved, look for a mistyped number or a proper name the word list may not know, fill in letters you’re sure of, and run it again.
- Small grids without free letters can have more than one valid answer, so always enter them when the puzzle includes them.
Ideas for the classroom and homeschool
- Grades 3–5Build a tiny 5 × 5 codeword from this week’s spelling list. Partners crack it, then use Check my letters to test their guesses before anything is revealed.
- Grades 6–8Connect it to math: tally how often each number appears in a newspaper codeword and compare the results with typical English letter frequency. Why might a number used only once be a rare letter like Z?
- Grades 9–12Have students write out the reasoning behind each letter they place, as a short logic exercise. Allow a single-letter reveal only when a group is truly stuck.
- Homeschool and familiesShare a weekend codeword with a ‘one hint each’ rule, so the reveal buttons are used sparingly and everyone keeps thinking.
Questions
Do I need the starter letters?
Not always – bigger grids can often be cracked from the number pattern alone. The free letters remove doubt, though, and on a small grid they may be the only route to a single answer.
Can students check their work without seeing the answers?
Yes. They type their letters into the boxes for each number and press Check my letters. Mistakes show in red; correct letters are left alone and the rest stays hidden.
What grid sizes does it support?
Any rectangle from 5 to 19 squares on each side. Rows and columns are set separately, so non-square grids are fine.
Opens Unscramble Words 4U, our free word-puzzle site, in a new tab. Free, with no sign-up.
Number-for-letter puzzles are a game, not a way to protect information – remind students never to use them for passwords or private messages.