Sudoku Made and maintained by Brian Hamilton and Karan Hamilton.
Brian builds the playable puzzle tools, while Karan helps test clarity, difficulty feel, and the player experience.
Playable puzzles and controls are tested in the browser for rule accuracy, usability, and a clear solving experience. See how we make and test puzzles, our editorial standards, or report a problem.
What is Easy Sudoku?
Easy Sudoku is classic sudoku at its gentlest. Fill the 9×9 grid so that:
- every row holds the digits 1 to 9 once;
- every column does too;
- and so does every 3×3 box.
Every board on this page starts with 40 of the 81 squares filled — always exactly 40 — and has exactly one answer. Better still for a first game, every one can be finished by looking alone: the only steps an Easy board ever needs are the two simplest in sudoku. The board above is saved in this browser, apart from the other level pages, so it is still there when you come back.
What does an Easy board ask of you?
We dealt 200 Easy boards from this page’s own generator and tried each one with a single step switched on. Hidden singles alone finished all 200. Naked singles alone finished 192; on the other eight a hunt for naked singles stalls somewhere, and one hidden single starts it again. No board needed anything more, and none had more than one answer.
| Level | Given digits | Singles alone finish | What the rest need |
|---|---|---|---|
| Easy | 40 | 200 of 200 | Nothing more |
| Medium | 32 | 200 of 200 | Nothing more |
| Hard | 26 | 171 of 200 | Locked candidates finish all 29 |
| Expert | 22–25 (median 23) | 135 of 200 | Locked candidates finish 47 more; naked pairs the last 18 |
200 boards a level, dealt by this page’s own generator and measured on 10 October 2026; every one had exactly one answer, counted by a separate solver. “Singles” means naked and hidden singles together. Nothing past naked pairs was needed on any board.
Easy and Medium both stop at singles. What separates them is the eight extra digits Easy starts with: more of the grid is settled, so the obvious move is more often right in front of you.
How do you spot a naked single?
A naked single is a square with one digit left: its row, its column and its box hold the other eight between them. In the board above each of the three rules out something the other two do not, which is the usual case, so read all three before you decide. The naked singles guide works through more of them.
How do you spot a hidden single?
A hidden single turns the question round. Instead of asking what a square can hold, ask where a digit can go. Pick a box and a digit it is missing, then follow the copies of that digit already on the board along their rows and columns: each one rules out a line of the box. When a single empty square is left uncovered, the digit goes there, whatever else that square could hold. It is the scanning most people do without naming it, and on Easy it is enough on its own. The hidden singles guide has more examples.
What is a good way to work through an Easy board?
- Take the digits one at a time and look for a hidden single in each box. A digit already placed six or seven times has the fewest places left, so start there.
- Where a row, column or box is down to two or three gaps, ask of each gap what it can still hold: that is where naked singles turn up.
- Every digit you place rules out squares for the next one, so look again around each placement before moving on.
- Notes are optional. If you like them, Start Notes fills in every candidate at once, and any square left with one digit is a naked single.
Singles finish every Easy board, and a correct digit never takes a single away. So whenever you are stuck, there is a naked or hidden single somewhere that has been missed — the board never needs anything harder. Go back to step 1 with the digit you have placed most.
Has this page always dealt boards like these?
No. The page went up on 28 March 2026, and until 13 April its generator took a full grid and blanked squares at random until 40 were left, without checking anything. We ran that generator again: 128 of 200 of its Easy boards had more than one answer. The game marks your digits against one stored answer, so on those boards a digit that broke no rule could still be marked as a mistake.
From 13 April every board was checked for a single answer, and on Easy that was enough: singles finished every Easy board then, as they do now. The page itself said an Easy puzzle has “around 38 to 45 filled cells”; the game has always dealt exactly 40. Since 10 October 2026 the generator also checks how each board can be solved, and every number on this page is measured from it.
What do the buttons do?
- Notes switches the keypad to pencil marks, and Start Notes fills every empty square with the digits it can still hold, in one go.
- Hint picks a square at random from the ones that are empty or wrong and puts its answer in. It does not explain the step and it is an ordinary move: Undo takes it back.
- Undo and Redo step back and forward through your moves (Ctrl+Z and Ctrl+Y, or Cmd on a Mac); Erase clears the selected square.
- A wrong digit turns red and adds one to the mistake count. There is no limit: the count never ends the game.
- Solve asks before it fills the grid. New Game deals another Easy board, and the level buttons above the grid switch level without leaving the page.
- The timer starts when the board is dealt and runs until it is finished. Your board, the clock and your notes are saved as you go.
Where next?
When Easy feels automatic, move up to Medium: the same two singles, with eight fewer digits to start from. For one new Easy board a day, the same for everyone, try Daily Easy Sudoku. Younger players can start smaller with 4×4 and 6×6 sudoku, or sudoku for kids, and if you would rather use a pencil, the printable sudoku page has PDFs at every level.