Play Sudoku Online for Free

SudokuIt lets you play free Sudoku puzzles online in Easy, Medium, Hard, Expert, Master, and Extreme difficulties.

Whether you're just starting out or solving advanced puzzles with ease, we offer a wide variety of sudoku games for every skill level. Practice free sudoku online anytime and boost your logical thinking on SudokuIt.com.

History of Sudoku

Sudoku, meaning "single number" in Japanese, is a logic-based puzzle that originated from a number placement game invented in the late 1970s. It gained worldwide popularity in the early 2000s and remains a favorite pastime for millions due to its mix of simplicity and challenge.

Sudoku Games for Every Level

At SudokuIt.com, you'll find puzzles to suit your current skill level, from first games that need nothing but singles to long solves that need advanced patterns. Each puzzle's level comes from its Sudoku Explainer rating.

How SudokuIt Grades Its Six Levels

Every puzzle on SudokuIt is rated with Sudoku Explainer, a free program that measures how hard a sudoku is to solve by logic. It works through the puzzle one step at a time and always takes the simplest technique that works. Each technique has its own rating, and longer chains rate higher. The hardest step in the solve becomes the puzzle's rating: 1.2 for the easiest puzzles on the site, 9.0 for the hardest. The rating sets the level. Givens, the digits printed at the start, count only for Easy, which needs at least 28 of them.

Easy: rated 2.3 or less, with 28 or more givens
Medium: rated up to 3.0
Hard: 3.1 to 5.4
Expert: 5.5 to 6.9
Master: 7.0 to 7.6
Extreme: 7.7 and up

Here is what the levels hold across the 3,341 puzzles on the site in November 2026:

Easy (484 puzzles): 30 givens each. All but four can be finished with singles alone, such as the hidden single.
Medium (1,521): nearly all start with 21 to 23 givens, most often 23. Singles alone finish nearly two in three. The rest need one more idea, such as a pointing pair or a naked pair.
Hard (258): none can be finished with singles. The hardest step is a wing such as the Y-Wing in 47%, a uniqueness pattern such as the unique rectangle in 34%, and a subset or a fish such as the X-Wing in the rest.
Expert (300): in 81%, the hardest step is a chain on a single digit, the kind the X-chain guide teaches. Most of the rest turn on a BUG or an XY-cycle.
Master (578): in 98%, it is a forcing chain that moves between digits, like an alternating inference chain.
Extreme (200): in 79%, the hardest step follows every candidate of one cell, or every place for one digit in a house, and keeps what they all agree on. The rest need a Nishio (15%) or a longer dynamic forcing chain (6%).

Above Easy, the number of givens tells you little: 2,833 of the 2,857 puzzles start with 21 to 23. Our technique guides walk through most of these patterns on real boards, from singles to forcing chains.

Tips to Get Started

Start with the easiest number: Look for numbers that already appear the most in the grid. Begin by filling in obvious gaps in rows, columns, or boxes.
Use pencil notes: Keep track of possible numbers in each cell: this makes solving complex puzzles more manageable and helps avoid mistakes.

New Challenge Every Day

Looking for a new puzzle each day? Our daily sudoku section posts one. Its calendar keeps earlier days open, and when you are logged in it marks the days you have solved.

How to Play Sudoku

The goal of sudoku is to fill a 9×9 grid so that every row, column, and 3×3 box contains the digits 1 through 9, with no number repeated in the same row, column, or box.

The rules are simple:

Each puzzle starts with some numbers already filled in.
Each row must include every number from 1 to 9 exactly once.
Each column must include every number from 1 to 9 exactly once.
Each 3×3 box must include every number from 1 to 9 exactly once.

You don't need math: just logic, patience, and observation.

Explore more information to improve your skills:

Sudoku Rules: learn the core principles behind the game
Solving Techniques: discover advanced strategies and logic methods

Start Playing Sudoku Today

Sharpen your logic, stay focused, and have fun with SudokuIt. Choose your difficulty, start solving, and enjoy the satisfaction of completing a puzzle, one number at a time.

Prefer paper? Print a puzzle and you get one puzzle on one page, with a short code next to the grid. Type sudokuit.com/p/ and the code, or scan the QR code on the sheet, and the same puzzle opens here as a game, with hints if you get stuck.

Start a Puzzle Now

What is SudokuIt.com?

SudokuIt.com is a modern, user-friendly sudoku platform where you can play sudoku in your browser, from a library of more than 3,000 sudoku puzzles. Our goal is to make sudoku accessible and enjoyable for everyone: from beginners learning the rules to experts mastering advanced solving techniques.