Sudoku with nothing in the way.
Sudoku Lab started from a simple question: why are sudoku apps so crowded? We stripped out everything that gets in the way and kept only what matters — a clean board, instant feedback and progression that makes sense. From Easy to Expert, every difficulty was tuned to be demanding without being unfair. And once you have the four levels down, Hardcore is waiting: ten Expert puzzles back to back, one mistake and the run is over. No sign-up, no subscription, no ad forced on you every move — just you, the board, and a Graphite & Amber theme built to look good at 2 in the morning.
What playing looks like
Features
4 Difficulty Levels
Easy, Medium, Hard and Expert — each with its own difficulty curve.
Daily Challenge
The same puzzle for everyone, every day. Build your streak.
Zen Mode
No lives, no pressure — just you and the board, at your own pace.
Hardcore
Ten Expert puzzles in a row. One mistake ends it. For players who already have it down.
Smart notes
Manual pencil marks, or auto-notes with a single tap.
Unlimited undo
Made a mistake? Step back as many times as you need, with no penalty.
34 achievements
From your first solved puzzle to a full Hardcore run.
Free, no sign-up
Progress saved on your device. No account, no friction, no catch.
How to play
Sudoku has a single rule: fill the 9×9 grid so that every row, every column and every 3×3 block contains the numbers 1 through 9 with no repeats. The numbers already on the board are your clues — everything else is deduced from them, never guessed.
Start with what is forced
Look for the row, column or block that already has the most numbers. Where a single cell is left, its value is forced. Every number you place opens up two or three more.
Use the notes
When a cell allows more than one number, write the candidates down instead of guessing. Sudoku Lab has both manual and automatic notes — one tap fills in every possible candidate.
Made a mistake? Step back
Undo is unlimited and costs nothing. In modes with lives, a mistake costs a heart; in Zen Mode it costs nothing at all.
Pick the mode by the time you have
Easy and Medium take a few minutes. Hard and Expert call for notes. Hardcore is ten Expert puzzles in a row, and one mistake ends the whole run.
Sudoku Lab questions
Is Sudoku Lab free?
It is. The whole game is unlocked from the moment you install it — no level, mode or feature sits behind a payment. It is supported by ads, and none of them appear in the middle of a round.
Does it work without internet?
The game works fully offline: puzzles are generated on the device, not downloaded. With no connection, only the ads stop loading — everything else stays the same.
Do I need an account?
No. There is no sign-up, login, email or password. You open the app and you are already playing.
Where is my progress kept?
On the device itself. Records, statistics and achievements are stored locally and never pass through a server. Switching phones means starting over.
Which devices does it run on?
iPhone and iPad through the App Store, and Android phones and tablets through Google Play. Both get the same updates.
Which languages is it available in?
Portuguese and English, following your device language.
Are there in-app purchases?
Not today. There is no currency, pass or item sold inside the game.
Sudoku Lab. Free. No sign-up.
Download now and start playing in under 10 seconds.