WORDOKU
Learn how to play Wordoku.
Wordoku is a word-based twist on classic Sudoku. Instead of numbers, each puzzle uses a unique 9-letter word with no repeating letters. Your goal is to fill the 9×9 grid using all nine letters so that the puzzle follows the traditional Sudoku rules.
Each row, column, and 3×3 box must contain all nine letters exactly once. The puzzle is solved when you fill in all the cells correctly.
Example 3×3 box:
Each 3×3 box must contain all 9 unique letters. Clues (darker) are given; you fill the rest.
Use the keypad to input letters. You can also use the "Erase" and "Undo" buttons to remove a letter or undo your last move if you make a mistake.
Erase
Clears the selected cell (removes both the letter value and any pencil marks). Only works on cells you've filled, not the given clues.
Undo
Reverts your last move. Works for both letter entries and pencil marks. Can undo multiple moves in sequence.
Pencil Mode
Toggle pencil mode to make small notes. When active, clicking letters adds them as pencil marks (small letters in a 3×3 grid) instead of setting the main value. Click the button again to exit pencil mode.
Pencil marks example:
Pencil marks appear as small letters in a 3×3 grid, arranged alphabetically based on the puzzle word. They help you track possible letters for a cell without committing to a value.
To add pencil marks, click the Pencil button to toggle pencil mode, then click letters on the keypad. Pencil marks are automatically cleared when you enter a solid letter value in that cell.
Wordoku is a great way to challenge your brain and improve your vocabulary.
Wordoku is solved with logic, not luck. Because the letters are just symbols standing in for numbers, every technique that works in classic Sudoku works here too. These tips will help you move from guessing to confident, methodical solving.
Start by looking for rows, columns, or 3×3 boxes that are already nearly full. If a box is missing just one or two letters, you can often place them immediately by checking which letters are absent. Clearing these obvious cells early opens up the rest of the grid.
Pick one letter and hunt for every place it can legally go. Because each letter appears exactly once per row, column, and box, a single letter can frequently be pinned down across the whole grid. This "cross-hatching" technique is the fastest way to break a puzzle open.
Each key on the letter pad shows how many cells still need that letter. When a letter reaches zero it disappears from the keypad, so you always know which letters are still in play and which are finished. Letters with only one or two remaining slots are usually the easiest to place next.
When a cell has more than one possibility, switch on Pencil Mode and note every candidate. As you fill in neighbouring cells, you can eliminate candidates until only one remains. Pencil marks turn a tricky guess into a clear deduction and keep the board tidy.
The highlighted main diagonal (top-left to bottom-right) spells the puzzle's hidden nine-letter word in order. You never need the word to solve the grid — it's always solvable with pure logic — but spotting a few diagonal letters can help you guess the word, and knowing the word lets you fill the rest of the diagonal for free. The full word and its dictionary definition are revealed when you finish.
Easy puzzles start with 36 or more given clues and can usually be solved by simple scanning. Medium, Hard, and Extreme puzzles give you progressively fewer clues (down to as few as 22), which forces you to rely on candidate marking and chains of deduction. Every puzzle is generated with exactly one solution, so if you get stuck, the answer is always there to be reasoned out — never guessed.
Wordoku is a word-based variant of Sudoku. Instead of the digits 1–9, each puzzle uses the nine distinct letters of a hidden nine-letter English word. Every row, column, and 3×3 box must contain each of those nine letters exactly once, following the same rules as classic Sudoku.
No. The puzzle is always solvable with pure logic, exactly like Sudoku. The highlighted main diagonal spells the hidden nine-letter word in order, so you can guess it as you go — but you never have to. Once you complete the grid, we reveal the word and its dictionary definition.
The Daily Puzzle is a single medium-difficulty puzzle that is the same for every player and refreshes once a day. It is a fun way to compare times with friends and to build a solving streak by playing every day.
Yes. The lightbulb button on the keypad reveals one correct letter in an empty or incorrect cell. Hints are optional and are tracked separately from mistakes, so you can challenge yourself to solve with as few as possible.
Yes. Wordoku is completely free to play in your browser. There are no accounts, downloads, or subscriptions. The site is supported by unobtrusive ads so the puzzles stay free for everyone.
Puzzles are generated on the fly from a library of over 4,700 nine-letter English words that contain no repeating letters. Combined with a randomised grid for each word, this means the supply of unique puzzles is effectively endless.
Difficulty is determined by how many starting letters (clues) you are given. Easy puzzles have 36 or more clues, Medium have 32–35, Hard have 28–31, and Extreme have as few as 22–27. Fewer clues require more advanced deduction.
Yes. Every puzzle is validated during generation to guarantee it has exactly one valid solution. That means the challenge always comes from logic — you can always reason your way to the answer without guessing.
Your current game is saved locally in your browser, so you can close the tab and return to an in-progress puzzle. Progress is stored on your device only and is not tied to any account.
Yes. Wordoku uses a responsive layout designed for touch, so it works on phones, tablets, and desktops. On mobile the letter keypad sits below the board for comfortable one-handed play.