Easy, Medium and Hard puzzles every day in Classic and Killer, the Classic Daily Challenge with its own leaderboard, and the Daily Triple for players who want a real fight.
Every day at midnight UTC, new puzzles unlock: an Easy, a Medium and a Hard Classic Sudoku, and the same three levels in Killer Sudoku. They are the same puzzles for everyone in the world, so you can compare your time against anyone — each one shows how many players have solved it and the fastest time. Practice mode gives you the full toolset — undo, redo, pencil marks, candidates, Auto Check, check-cell and check-puzzle — so it is a comfortable place to learn rather than a test.
A calendar view tracks which days you have completed. Finishing a day keeps your streak alive; missing one resets it. Past days stay open, so you can go back and clear a puzzle you skipped — that fills the calendar square, though it will not restore a broken streak. Practice solves are not ranked at all: the daily leaderboard belongs to the Classic Daily Challenge, which is today-only.
The Classic Daily Challenge is the competitive version and it plays very differently. It is Hard difficulty only, you get exactly one attempt per day, and the assist tools are switched off — no undo, no redo, no candidate display, no check-cell or check-puzzle, and the solver refuses the puzzle outright. The board stays covered until you press Start; the clock begins there — and that is also the moment your one attempt for the day is spent, so opening the puzzle and backing out costs you nothing. Once it is running it cannot be paused.
Finish and your time goes on that day's leaderboard, which is kept for seven days. If you get stuck there is a Give Up button: it submits the attempt and closes out your day rather than leaving the run hanging. Because there is only one attempt, it rewards a clean first pass over a fast reckless one.
The Daily Triple is the elite event: three puzzles — a Classic grid, a Symmetric grid and a Shape puzzle — drawn from the Extreme and Diabolical pools. All three are open from the start and you can take them in any order, but only one at a time: a puzzle you have begun must be finished or given up before you can open another, and all three must be played on the day they are issued.
All three puzzles feed one combined live leaderboard, with a crown on whoever holds first place. Unlike the Classic Daily Challenge board, Daily Triple results are kept permanently, so the archive builds into a real record over time. Results are recorded and scored on the server — your time and the puzzle’s score are written server-side — and the whole event rolls over strictly at UTC midnight with no grace period.
Every daily feature on the site keys off the same UTC date. At 00:00 UTC the practice puzzles, the Classic Daily Challenge and all three Daily Triple puzzles change together — there is no staggered release and no grace window on either side. If you are mid-solve when the day turns, finish before midnight: the puzzle you are holding belongs to the day it was issued.
That also means the "best time" you are chasing on the leaderboard is always a same-day time. Depending on where you live, the reset may land in the middle of your afternoon rather than overnight — worth knowing before you start a ranked run twenty minutes before the hour. The countdown on the Daily page shows that moment in your own local time.
Yes. The Classic and Killer practice puzzles, the Classic Daily Challenge and the three Daily Triple puzzles are identical for every player worldwide on a given date, which is what makes the leaderboards meaningful.
Practice puzzles can be replayed freely. Ranked, and each of the three Daily Triple puzzles, allow exactly one attempt per day — giving up counts as your attempt.
The streak resets. Completing a past day from the calendar fills that square and counts toward your record, but it does not restore a broken streak.
The Classic Daily Challenge, tournaments, duels and the Daily Triple all disable undo, redo, candidate display, check-cell and check-puzzle, and the solver refuses those puzzles, so every player is solving under identical constraints. Pencil marks and cell colouring stay available in every mode. Practice keeps the full toolset.
Classic Daily Challenge leaderboards are kept for seven days. Daily Triple results are kept permanently.