Today's sudoku

How today's sudoku works

Every day there is one NineByNine sudoku in four levels: easy, medium, hard and expert. On a given date everyone gets the same four puzzles, so you can compare times with friends or a crossword group without spoilers. The puzzle day follows your own calendar: the new set appears at midnight local time, wherever you are. If it is still Tuesday where you live, you see Tuesday's puzzle, even if it is already Wednesday somewhere else.

Choose a level with the tabs above the grid. Each level keeps its own progress, timer and notes, so you can start the easy puzzle over breakfast and come back to the expert one in the evening. Your games save automatically in this browser; there is no account and nothing to sign up for.

The rules in thirty seconds

Fill every empty cell with a digit from 1 to 9. Each row, each column and each of the nine 3×3 boxes must contain every digit exactly once. The numbers printed in the grid at the start (the givens) never change. That is the whole game: there is no arithmetic, and every NineByNine puzzle has exactly one solution that you can reach by logic alone, without guessing. New to sudoku? The step-by-step guide walks through a first puzzle.

Tools that help without spoiling

• Notes (pencil marks). Turn on notes mode, or hold Shift while typing a digit, to jot down the candidates for a cell. With “Auto-remove notes” on, placing a digit clears it from the notes in the same row, column and box.
• Hints in three steps. The first press tells you which technique to look for and where; the second highlights the cells involved; the third makes the move and explains it. If one of your numbers is wrong, the hint says so first. Hints are counted and shown when you finish.
• Mistakes. Two equal digits in a row, column or box are always marked. Turn on “Highlight mistakes” to also mark numbers that don't match the solution, or press Check once to see how you are doing.
• Undo and redo remember up to a thousand moves, and the timer pauses by itself when you switch tabs or put your phone away. Press Pause to hide the grid while you take a break.

What the four levels mean

Difficulty is not guessed from the number of givens. Our solver works through each puzzle the way a person would and records the hardest technique it needs:

• Easy puzzles fall to hidden singles and naked singles alone, and start with 36 to 40 givens.
• Medium adds pointing pairs, box/line reduction, and naked or hidden pairs.
• Hard can need triples, the X-Wing or the XY-Wing.
• Expert can need the Swordfish, Jellyfish, XYZ-Wing, a unique rectangle or simple coloring.

No level ever needs chains or trial and error. The table above lists the exact techniques for each of today's puzzles, and the strategy guides explain them with diagrams and practice puzzles.

Streaks, stats and sharing

Solve any level of today's puzzle to extend your daily streak. Your best and average times for each level, the number of puzzles you have solved and your streak are kept only in this browser. When you finish, you can copy a short result line that shows the date, level, time and hints, but not the grid, so it never spoils the puzzle for anyone else. You can clear everything with “Delete all my data” on the privacy page.

Yesterday's puzzle, printing and more

Missed a day? Every puzzle since Monday, September 21, 2026 stays playable in the archive, with a calendar for each month. Prefer paper? Press Print under the grid, or make a sheet of puzzles with answers on the printable sudoku page. If you want more puzzles than one a day, unlimited mode has thousands at every level, and the solver can explain a puzzle from a newspaper or book step by step.