Treptes Sudoku: free Sudoku that teaches you
Classic Sudoku, free in your browser, built to make you a better solver. Every puzzle can be solved with logic alone, and every hint explains the reasoning, so you learn a little more with each game.
How to play
Fill the 9×9 grid so that every row, every column and every 3×3 box contains the numbers 1 to 9, each exactly once. Some numbers are given at the start; the rest you work out. New to Sudoku? Our step-by-step guide gets you solving in a few minutes.
What makes it different
- Hints that teach. A hint shows the next logical step in stages and names the technique. Techniques you discover are collected in your profile.
- A puzzle for your level. Three quick questions and two placement puzzles set your starting rating. After that, your rating moves with every game you finish.
- Daily Challenge. One shared puzzle a day, at the right difficulty for you, with streaks and a calendar of the days you solved.
- Genius Gauntlet. Three Genius puzzles every month for the players who want the hardest logic.
- Medals and records. Best times, clean solves without hints or mistakes, and medals for the milestones along the way.
- Ads that respect the game. Never during a puzzle, never on pause, and the first new game of the day is always ad-free.
Difficulty levels
Difficulty is set mainly by the hardest technique a puzzle needs, not just by how many numbers are given. That is why a Treptes “Hard” is hard for the right reasons.
- Easy
- Solved with the two basic techniques: the last number that fits a cell, and the only cell a number fits in a row, column or box.
- Medium
- Fewer numbers given, and sometimes locked candidates: a number that, inside a box, can only sit on one line.
- Hard
- Pairs and triples: groups of cells that share the same few candidates.
- Genius
- The advanced patterns: X-Wing, Swordfish and XY-Wing. Still pure logic, never a guess.
Frequently asked questions
Is Treptes Sudoku free?
Yes. Easy, Medium and Hard puzzles, the Daily Challenge, your rating, medals and statistics are free. Premium adds the Genius level, the Genius Gauntlet, unlimited hints and no ads.
Do I need an account?
No. You can play straight away and your progress is saved in your browser. An optional account will let you keep your progress across devices.
Can every puzzle be solved without guessing?
Yes. Every puzzle is checked when it is created: it must be solvable step by step with techniques our hints can explain.
What is the Daily Challenge?
One new puzzle every day, at a difficulty that matches your level. Solve it every day to build a streak.
How do hints work?
If you made a mistake, the hint points to it first. Otherwise it shows you the next logical step in stages: where to look, what to notice, and finally the move, with the name of the technique.