Sudoku
Fresh puzzles in easy, medium and hard - with hints and validation
100% free. Runs entirely in your browser - your files and data never leave your device and nothing is uploaded to any server.
- Fill every row, column and 3×3 box with 1 to 9.
- Pick a cell, then tap a number - or type it.
- Arrow keys move, Backspace clears.
About this tool
Fresh Sudoku puzzles in easy, medium, and hard difficulty, complete with hints and real-time validation - fill the 9x9 grid so every row, column, and 3x3 box contains all digits 1-9 exactly once.
How to use this tool
- Select difficultyStart easy/medium/hard based on solving confidence.
- Fill obvious numbers firstUse row, column, and box elimination basics.
- Apply logic progressionResolve candidates and reduce uncertainty systematically.
- Complete valid gridFinish puzzle with each number appearing once per unit.
How to play sudoku
The 9 x 9 grid is split into nine 3 x 3 boxes. Fill every empty square with a digit from 1 to 9 so that each row, each column and each box contains every digit exactly once. The numbers already given cannot be changed.
Start with the rows, columns or boxes that are nearly full, and look for the only place a digit can go. Easy puzzles can be solved this way alone; medium and hard need you to rule out candidates. If you get stuck, ask for a hint.
Key features
- Improves logical reasoning and concentration.
- Difficulty modes support all skill levels.
- Hints and validation aid learning process.
- Great daily puzzle for cognitive fitness.
Common uses
- Daily logic practice routine.
- Classroom reasoning exercises.
- Relaxed no-rush puzzle sessions.
- Timed challenge competitions.
Tips for better results
- Start with singles before advanced techniques.
- Check each 3x3 box after every few placements.
- Use hints sparingly to preserve learning value.
- Pause and rescan if you feel stuck.
Mistakes to avoid
- Guessing randomly too early.
- Ignoring duplicate conflicts in units.
- Overusing hints and skipping logic.
- Rushing hard puzzles without method.
Frequently asked questions
Check the specific hint implementation - some reveal a single correct cell, while others might just highlight a cell you've made a logical error on without directly giving the answer.
Real-time validation typically flags conflicts (like a repeated number in a row/column/box) as you enter them, helping you catch mistakes immediately rather than discovering them much later.
Well-built Sudoku generators ensure each puzzle has exactly one valid solution, which is a core requirement for a properly designed Sudoku puzzle (rather than one with multiple possible answers).
Look for 'naked singles' - cells where only one digit is possible - and 'hidden singles', where a digit can go in only one cell of a row, column or box. Those two solve most easy puzzles.
Noting the possible digits in each cell lets you spot pairs and patterns that eliminate options elsewhere. Hard puzzles usually need them; easy ones rarely do.
A well-made puzzle can be solved by logic alone. If you feel you must guess, look again for pairs or a digit that fits in only one place in a row, column or box.