Every row, column and box must contain each number exactly once. Every puzzle here has exactly one solution.
SizeDifficulty
Time 0:00
Name: ______________ Date: ______________
Sudoku · cerebite.com
How to play
Tap an empty cell, then tap a number (or type it on a keyboard). In a 9×9 grid each row, column and 3×3 box needs the digits 1–9; the 6×6 uses 1–6 with 2×3 boxes, and the kid-friendly 4×4 uses 1–4. "Highlight mistakes" instantly marks any number that clashes with its row, column or box. Every puzzle is generated fresh with a mathematically verified single solution — no guessing required, logic always wins. Press Print for a clean paper version: your pencil marks are left out, so the sheet shows only the original clues.
Yes — the generator first builds a complete valid grid, then removes numbers one at a time, and after every removal it re-solves the puzzle to confirm exactly one solution remains. If a removal would create a second solution, the number stays.
Which size should a beginner start with?
Start with 4×4 to learn the one-of-each rule, move to 6×6 to practice box shapes, then take on the classic 9×9 on Easy. The rules never change — only the amount of logic you chain together.
Can I print puzzles to solve on paper?
Yes — press Print and you get a clean sheet with only the original clues (your on-screen entries are excluded), a name/date line, and no ads or buttons. In the print dialog you can also choose "Save as PDF".
What are the basic sudoku strategies for beginners?
Start by scanning: pick a number and check which cells in each box can still hold it. Fill cells that have only one possible value (naked singles), and use pencil marks to note candidates. Most Easy and Normal puzzles fall to just these techniques.
What is the minimum number of clues a sudoku can have?
17. In 2012, mathematicians proved by exhaustive computer search that no 9×9 sudoku with 16 or fewer clues can have a unique solution — every proper puzzle needs at least 17 givens.
Is sudoku good for your brain?
It exercises logical deduction, working memory and concentration, and many people find a daily puzzle a relaxing mental routine. It makes you better at the skills you practice — think of it as enjoyable training rather than a medical treatment.