A reason to return every day
The date creates one verified board for everyone. Your completion and streak stay in this browser, so CalmSudoku remains guest-first and never needs your email address.
Same day, same board
Refresh, close the tab, or come back later—the day’s board stays the same until your local date changes.
Private on-device streak
Finish on consecutive days to grow your streak. The record is stored only on this device and is not tied to an account.
New to Sudoku?
Read the step-by-step beginner guide, review the three essential rules, or learn how to solve hard Sudoku logically.