Pick a difficulty and press Make a sudoku. A fresh puzzle is generated in your browser and checked to have exactly one solution. Click a cell and type a number, or tap a cell and use the keypad on your phone. Turn on Notes to pencil in candidates, and the keypad shows how many of each digit are left. Check marks mistakes, Undo takes back a move, and Reveal shows the answer.
Many sudoku generators charge to print, put a watermark on the page, cap how many you can make, or ask you to sign up first. This one doesn't. There's no account, no email wall, and no limit. Every puzzle has a share link that holds the whole grid, so a teacher can send one to a class or you can text one to a friend. It's a free alternative to sudoku.com, Web Sudoku and Discovery Education's Puzzlemaker, and it works on phones, tablets, Chromebooks and laptops.
Each puzzle starts as a complete, valid grid. Numbers are removed in symmetric pairs, and after every removal the puzzle is re-solved to confirm there is still only one answer. No dead ends, no puzzles with two solutions. Easy starts with about 40 clues; Hard and Expert with around 28 or fewer. Your progress, including pencil marks, is kept in the page address, so a refresh doesn't lose your place.
Printing gives you the title and the grid with no site header, footer or ads. Print it blank for solvers, or press Reveal first for an answer key. Good for classroom worksheets and early finishers, sub plans, club and church newsletters, brain games for seniors and memory care, waiting rooms, and a daily coffee-break puzzle.