Coffee Sudoku
Where Coffee Meets Numbers
Classic Sudoku, quiet interface
Three Hidden Modes
Unlock them by playing
Errors stay hidden, the mistake counter is gone, and you solve at your own pace. No scoring, no pressure.
Unlock by completing Very Hard mode once
Numbers vanish after 15 seconds, then every 20 seconds after that. You need to remember what disappeared. Think of it as Sudoku with a memory exam bolted on.
Unlock by winning Zen Mode once
The board starts empty. Instead of given digits, you get cages with target sums. No digit repeats inside a cage. It is a different kind of Sudoku that forces you to think about arithmetic and elimination at the same time.
Unlock by winning Redacted Mode once
Why Coffee Sudoku?
Completely Free
No ads, no purchases, no subscriptions.
Privacy First
No data collection. Your progress is stored locally on your device.
10 Languages
Play in English, Spanish, French, German, Italian, Portuguese, Romanian, Slovak, Japanese, or Polish.
Fully Accessible
Works with screen readers and other assistive tools.
Sudoku hub
Three places to go
A web board to play, a learning path with every technique, and a blog with strategies and tips.
Play Sudoku online
A free web puzzle with classic, Zen, and Redacted modes.
Sudoku Academy
A guided path from the rules to expert techniques, including a full Killer Sudoku zone.
Sudoku blog
Guides, strategies, and notes on staying sharp with regular practice.