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About this tool
Play a shared daily sudoku or unlimited puzzles with notes, hints, streaks, and four difficulty levels.
This Sudoku plays a shared daily puzzle — seeded from the calendar date, so every player worldwide gets the identical grid — plus unlimited puzzles at easy, medium, hard and expert. Every grid is generated by carving clues out of a solved board in rotationally symmetric pairs and keeping a removal only when the puzzle still has exactly one solution, so nothing is ever guessable two ways. Pencil-mark notes, conflict highlighting, hints and a daily completion streak are all built in.
Open Sudoku — Daily Puzzle & Unlimited on AltFTool — it loads instantly in your browser.
Pick the 'Daily Challenge' tab for today's shared puzzle or 'Unlimited' with Easy, Medium, Hard or Expert, then press 'Play today's puzzle' or 'New game'.
Select a cell and fill it from the 'Number pad'; toggle 'Notes' for pencil marks, or use the 'Hint' and 'Check' buttons when stuck.
Solve the grid to log your Time, Mistakes and Hints — finishing the daily puzzle extends your day streak, which is saved in your browser.
Each clue removal is tested with a solution counter and reverted if it creates a second answer, so no grid ever requires guessing.
Easy, medium and hard land on exactly 40, 32 and 26 clues every time. Expert targets 22 but the uniqueness check often stops it a little short, so expert puzzles typically settle around 22-26 clues instead of being labelled by feel.
The board, your notes, the timer and your daily completion history are stored locally, so you can close the tab mid-puzzle.
Yes. The daily puzzle is generated from a seed derived from the calendar date, so the same date produces the same grid for every player, and it changes at local midnight.
Easy leaves 40 given numbers, medium 32 and hard 26, out of 81 cells. Expert targets 22 but the solution-uniqueness check often can't remove that many, so expert puzzles usually land around 22-26 clues. Fewer clues means more of the grid has to be deduced, which is what makes the harder levels slower rather than trickier arithmetic.
No. During generation each pair of cells is only cleared if the remaining grid still solves exactly one way, verified by a solver that stops as soon as it finds a second solution. A puzzle with two answers is never served.
It counts consecutive calendar days on which you finished that day's daily puzzle, and it also keeps your longest run and lifetime total. Missing a day resets the current streak but leaves the longest one intact.