Daily Sudoku
One puzzle a day, the same one for everyone
Every other board on this site is generated fresh for you the moment you open it. This one is not. The daily puzzle is built from the date itself, which means the grid you are looking at is character-for-character the grid everyone else opening this page today is looking at — and it stays that way until midnight UTC.
That is a small technical difference with a large practical one. When everyone solves a different puzzle, a time of four minutes thirty tells you nothing: it might have been an unusually open grid, or an unusually mean one. When everyone solves the same puzzle, the same four minutes thirty is a real comparison, against other people and against yourself on previous days.
Four puzzles, not one
There is a separate daily grid at each of the four levels — easy, medium, hard and expert — and they are four unrelated puzzles rather than one puzzle with clues added and taken away. Solving today's easy board gives you nothing towards today's expert board.
Switch between them freely with the buttons above the grid. Each level keeps its own progress, so leaving a half-finished hard puzzle to try the easy one and coming back later costs you nothing. A level you have already finished today is marked with a tick.
When it resets, and why UTC
The puzzle changes at midnight UTC, not at midnight where you are. That is deliberate, and it is the same clock the daily leaderboard runs on. If the puzzle rolled over at local midnight, a player in Auckland and a player in Los Angeles would be solving different grids while posting to the same board, and the ranking would be meaningless for most of the day. One clock for everyone is the only version that works.
In practice this means the day turns over at a different wall-clock time depending on where you are — early evening in the Americas, early morning across Europe, lunchtime or later across Asia and the Pacific. The countdown at the top of this page always shows how long today's grid has left.
Posting your result
Finish a daily puzzle and you can put the result on the daily and weekly boards with nothing but a nickname — no account, no email, no password. Scoring is the same as everywhere else on the site: ten points for each square you fill in correctly yourself, a completion bonus for the level, a speed bonus for beating the par time, and deductions for mistakes and hints.
You can restart a daily puzzle as often as you like, and the board you post is whatever run you actually completed. Nothing stops you from taking a second or third attempt at a grid you already know — but a time earned that way is a time earned that way, and most of the satisfaction of a daily comes from the first cold run at it.
Streaks, and what is actually being counted
A day counts towards your streak once you have finished any one of the four levels on it. Doing all four is worth more in the record below, but it does not extend the streak further than doing one — the point of the number is turning up, not grinding.
The streak breaks when a day passes with nothing solved on it. It does not reset the moment the clock rolls over: a run that ended yesterday still reads as a live streak for the whole of today, because today has not been missed until it is over. Miss today entirely and it is gone tomorrow.
Everything in your record — the streak, the days played, the best time and score at each level — is computed from results saved in your own browser. There is no account, nothing is uploaded, and nothing is shared between devices: open the site on a phone and it starts from zero there. Clearing your browser data clears it too. The one thing that does leave your device is a score you deliberately post to the leaderboard, and that carries only a nickname.
When today's puzzle will not open up
Because there is only one of each level per day, a daily puzzle is a worse place than usual to be stuck — you cannot simply deal a new grid. The useful move is to work out which deduction you are missing rather than to stare harder.
On an easy or medium grid, that is almost always a hidden single: a digit with only one remaining home in a row, column or box, which is invisible until you check the box rather than the square. On hard, it is usually a naked pair or pointing pair clearing candidates you have not written down. On expert, it tends to be an X-Wing, which spans two rows and two columns at once and will never be found by looking at one unit at a time.
If you are not using pencil marks yet, start — on the harder levels they are not an optional convenience but the thing the deductions are made of. The guide to notes covers when to write them and when they go stale, and the full techniques guide walks through every method in the order you actually need them.
If you would rather not wait
The daily puzzle is a fixed ration by design, and it is not meant to be the only thing here. The main board deals a fresh puzzle at any level as often as you want one, the four level pages do the same with a guide to what that level demands, and the printable sheets generate puzzles to take away from the screen. Stuck on a grid from somewhere else entirely? The solver will tell you not just the answer but whether that puzzle has one solution at all — which is often the real reason a grid refuses to work out.
New to the puzzle? The rules take about five minutes, and the FAQ covers what comes up next — including the question everybody asks, which is whether a Sudoku ever requires guessing. It does not.