Play sudoku online, free, from easy to expert
This is a full sudoku game you can play straight away in your browser: a 9×9 grid, the digits 1 to 9, and one rule — every row, every column and every 3×3 box must contain each digit exactly once. Pick easy, medium, hard or expert, or open the daily puzzle that everyone gets on the same date, and start filling cells.
Every puzzle is generated fresh on your device and checked to have exactly one solution. Difficulty is not just a count of clues: each grid is solved by a human-style solver first, and it is labelled by the techniques it actually needs, so a hard puzzle really does call for pairs, triples or an X-wing rather than luck.
It works as well on a phone as with a keyboard: tap a cell and a large number button, or use the arrow keys and digits. Notes, unlimited undo, explained hints and an automatic save let you stop and resume at any time. Nothing is uploaded and there is no account. Fancy a change of pace? Try Minesweeper or the 2048 game.
How to play sudoku here
- Choose a level — Easy, Medium, Hard or Expert — and press New game, or press Daily puzzle for today’s shared grid.
- Tap an empty cell. Its row, column and box are shaded, and matching digits light up.
- Tap a digit on the number pad or type 1–9. Press Notes (or N) to write small pencil marks instead; Shift + digit adds a single note without switching modes.
- Made a slip? Undo and Redo (Ctrl+Z, Ctrl+Y) step through every change, as far back as you like. Backspace erases a cell.
- Stuck? Hint explains the next deduction in words and highlights the cell; Reveal fills in one correct digit.
- Fill the last cell correctly and the grid celebrates. Times without revealed cells count as bests.
Sudoku — Play Online Free features
Graded by technique
Easy needs only singles, medium needs locked candidates, hard needs pairs, triples or an X-wing, and expert needs swordfish, XY-wings or chains.
Hints that teach
Instead of just filling a cell, the hint names the step — “Hidden single in box 5: 6 can only go in row 4, column 7” — and lists any eliminations that lead to it. Wrong digits are pointed out first.
Notes that tidy themselves
Pencil marks are removed automatically from the row, column and box when you place a digit, and undo puts them back exactly.
Conflicts and mistakes
Clashing digits are shaded red (switch this off for a purer game). Wrong digits count as mistakes, with an optional three-mistake limit.
Daily puzzle
The daily grid is generated from the date, so friends on the same day solve the identical puzzle. The level rotates through the week.
Saves itself
The game, timer, notes and full undo history are stored in your browser, so a reload resumes where you were. The timer pauses when you switch tabs.
Sudoku solving techniques, from singles to X-wing
The hint explains these techniques by name; the info line lists the hardest ones each puzzle needs.
| Technique | Level | What it means |
|---|---|---|
| Full house | Easy | A row, column or box has one empty cell left, so it takes the missing digit. |
| Hidden single | Easy | Within a row, column or box, a digit fits in only one cell. |
| Naked single | Easy | A cell sees eight different digits, so only one candidate remains. |
| Pointing / box-line reduction | Medium | All candidates for a digit in a box share one row or column (or the reverse), so that digit leaves the rest of the line or box. |
| Naked and hidden pairs, triples | Hard | Two or three cells in a unit share two or three candidates between them, so those digits can be removed from the other cells, or the other candidates from those cells. |
| X-wing | Hard | A digit is confined to the same two columns in two rows, so it can be removed from the rest of those columns. |
| Swordfish, XY-wing, chains | Expert | Three-line fish patterns, a pivot cell with two wings, or longer chains of reasoning. |
How the puzzles are made
A complete grid is filled at random by backtracking. Clues are then removed one at a time in random order. For easy and medium puzzles, a clue is only removed if the grid can still be solved using that level’s techniques; for hard and expert, a fast solution counter confirms that exactly one solution remains. The finished grid is solved again step by step, always using the simplest available technique, and kept only if the hardest step matches the chosen level.
Easy grids keep 36 clues, medium 30 and hard about 24–27; expert grids mostly have 22–26 clues and often minimal, meaning no clue can be removed without allowing a second solution. Sudoku needs at least 17 clues for a unique answer, so every level stays above that floor. For printable batches with answer keys use the Sudoku Generator, and to check a puzzle from a newspaper use the Sudoku Solver.
Sudoku — Play Online Free FAQ
Is this sudoku free to play online?
Yes. It is free with no sign-up and no download. It runs entirely in your browser on phones, tablets and computers.
Does every sudoku have only one solution?
Yes. Each generated puzzle is checked with a solution counter and with a step-by-step logical solver before it is shown, so there is exactly one correct grid and you never need to guess between two answers.
What does the hint do?
It first tells you about any digits that do not match the solution. Otherwise it finds the next logical deduction from the digits on the board, explains it in plain words and highlights the cell, without filling it in. Reveal places one correct digit.
Will I lose my game if I close the tab?
No. The current game, notes, mistakes, timer and undo history are saved in this browser after every move and resume on your next visit. Only one game is kept at a time, so starting a new one replaces it.
How is the daily puzzle chosen?
It is generated from the date (in your local calendar), so everyone who opens it on that date gets the same grid. Monday is easy, Wednesday and Friday are hard, Saturday is expert and the other days are medium.
Can I play sudoku with a keyboard or a screen reader?
Yes. Arrow keys move around the grid, digits place numbers and N toggles notes. Each cell is announced with its row, column and contents, and placed digits, conflicts and the finish are read out.