Sudoku

About Sudoku

Sudoku is the world's favourite number puzzle, and this version plays free in your browser on a phone, tablet or computer, with no download and no account. The rules fit in one sentence: fill the 9×9 grid so that every row, every column and every 3×3 box contains the digits 1 to 9 exactly once. There is no arithmetic involved, only logic. Every puzzle here has exactly one solution, and you can always reach it by reasoning, never by guessing.

Puzzles come in five difficulty levels, and each one is generated fresh, so you will never run out. Rather than just counting how many numbers are given, every puzzle is graded by solving it the way a person would and noting the hardest technique it needs. Easy puzzles start with 38 or more clues and fall to simple singles, which makes them perfect for learning. Medium puzzles give fewer clues and ask you to spot hidden singles. Hard puzzles need pointing pairs, box-line reductions and naked or hidden pairs. Expert puzzles call for X-Wings, Swordfish, XY-Wings and triples. Extreme puzzles cannot be cracked by any of those and reward patient, deep analysis.

A new Daily Sudoku arrives every day, and it is the same puzzle for every player, so you can compare times with friends. Like a newspaper puzzle it gets harder through the week: easy on Monday and Tuesday, medium midweek, hard on Friday and Saturday, and an expert puzzle on Sunday. Solve it every day to build a streak.

The game is designed to stay out of your way. Tap a cell and then a number, or use the keyboard on a computer. Notes mode lets you pencil in candidates, and placing a number automatically clears it from the notes in its row, column and box. Selecting a number highlights every copy of it on the board, the keypad shows how many of each digit are still to place, and completing a row, column or box gives a little flash. Undo is unlimited. If you get stuck, a hint fills in one cell and tells you why it has to be that number, so you learn the technique instead of just getting the answer. Mistakes can be shown in red as you go, or turned off for a tougher, pen-and-paper style game.

Your game saves automatically after every move, so you can close the tab and continue later on the same device. The statistics page tracks games won, best and average times and perfect games (no mistakes, no hints) for each difficulty, along with your daily streak. There is a dark theme for evening play, the timer pauses whenever you switch away, and the whole game is a small download that loads in a moment even on a slow connection.

Genre

Puzzle

Released

October 20, 2026

Platform

Web browser (phone, tablet, desktop)

Price

Free

Developer

FDZ Labs Inc.

Features

• Five difficulty levels, from Easy to Extreme, graded by the solving techniques each puzzle needs
• A new Daily Sudoku every day, the same for every player, with streaks
• Unlimited fresh puzzles, each with exactly one solution
• Notes with automatic clean-up, number highlighting and digits-left counters
• Hints that explain why a number goes where it goes, plus unlimited undo
• Statistics with best times and perfect games; light and dark themes; autosave

How to play

1. Fill every empty cell with a number from 1 to 9.
2. Each row, each column and each 3×3 box must contain every number from 1 to 9 exactly once.
3. Tap a cell to select it, then tap a number on the keypad to place it. Tap the same number again to remove it.
4. Turn on Notes to pencil in the numbers a cell could be. Placing a number clears it from the notes around it.
5. Use Hint if you are stuck: it fills in one cell and explains the reasoning. Undo takes back any move.
6. The puzzle is solved when the grid is full and every number is correct.

Controls

Tips and strategy

• Start with the numbers that already appear most often on the board. With seven or eight placed, the last few are easy to find.
• Scan each 3×3 box for a missing number and check which of its empty cells are blocked by that number in their row or column. If only one cell is left, that is a hidden single.
• Pencil in candidates once the easy moves run out. A cell with only one candidate left is a naked single.
• If a number can only go in one row or column inside a box, it cannot go anywhere else in that row or column outside the box (a pointing pair).
• Two cells in a unit that can only hold the same two numbers form a naked pair: remove those numbers from every other cell in the unit.
• Never guess. Every puzzle here has one solution that can be found by logic, so if you feel you must guess, look for a pair or a pointing line you have missed.