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How to Play Sudoku Online for Free: 7 Best Sites

There are many ways how you can flex your mental muscles and have a lot of fun at the same time, but you would be hard-pressed to find one that’s as accessible, engaging, and challenging as Sudoku.

Quick navigation:

  1. What Is Sudoku?
  2. How to Play Sudoku?
  3. How to Create a Sudoku Puzzle?
  4. Best Sites to Play Sudoku Online for Free
    1. Sudoku Online
    2. Web Sudoku
    3. Sudoku Kingdom
    4. 247 Sudoku
    5. Sudoku Solver
    6. Sudoku Menu

Even if you don’t like math and always rely on a calculator, there’s a pretty good chance that you’ll fall in love with Sudoku and the numerous benefits of playing it, including improved memory, increased concentration, and a better sense of time.


What Is Sudoku?

what is sudoku explained

Sudoku is a puzzle game that tasks its players with filling a 9×9 grid with digits so that each of the nine 3×3 subgrids, as well as each column and each row, contains all of the digits from 1 to 9. This task is made more difficult by the fact that the typical Sudoku puzzle has certain digits pre-filled.

The present-day version of Sudoku was first published in 1979 by Dell Magazines, a company known for its many puzzle magazines and astrology magazines. It’s believed that it was designed by Howard Garns, a 74-year-old retired architect who liked to spend his free time designing puzzles, because Dell Magazines included his name on the list of contributors.

Dell Magazines published the puzzle game as Number Place. It wasn’t until Maki Kaji, the president of Japanese puzzle manufacturer Nikoli, abbreviated the Japanese version of the game (Sūji wa dokushin ni kagiru or “the digits must be single” in English) when it first appeared under its current name: Sudoku.

Sudoku quickly spread outside Japan, appearing alongside crosswords and other puzzle games in major newspapers around the world. Today, the market is saturated with books of Sudoku puzzles, Sudoku video games, and Sudoku websites, so Sudoku players of all skill levels can enjoy this addictive puzzle game anywhere and at any time.


How to Play Sudoku?

how to play sudoku

One great thing about Sudoku is that it has very simple rules:

  • You must fill in all cells (there are 81 cells in total, stacked nine high and nine wide) with numbers from 1 to 9.
  • You’re not allowed to use the same number more than once in any row, column, or block when filling in the empty cells.
  • At least 17 numbers must be pre-filled (typically, 22 or 30 numbers are pre-filled).

The challenge comes from the fact that each cell in a Sudoku puzzle has only one correct answer because of the placement of pre-filled cells.

There are many Sudoku-solving techniques out there, but you don’t need to worry about them at all if you’re just starting and have never won a game of Sudoku before. Instead, we recommend you pick a Sudoku puzzle with a large number of pre-filled cells so that the path to the one and only correct solution is shorter.

Always start by identifying all sole candidates, which are cells that can contain only one specific number. When all other numbers but the candidate number exists in either the current block, column, or row, you’ve found a sole candidate.

From there, scan blocks, columns, and rows for cells with the fewest possible candidates and use a pencil to write them down. When you make a decision, immediately study how it affected other cells and adjust your strategy if needed.


How to Create a Sudoku Puzzle?

To create a Sudoku puzzle:

  1. Grab a sheet of paper, a pencil, and a ruler.
  2. Draw a large square and divide it into a 3×3 grid to end up with 9 smaller squares.
  3. Divide all 9 squares into 3×3 grids to end up with 81 cells.
  4. Fill in all cells according to the rules of Sudoku.
  5. Start randomly removing digits until you’re left with only 17 to 30 filled cells.

Alternatively, you can save yourself a lot of work by using an online Sudoku generator, such as OpenSky, which outputs a printable PDF document with up to four Sudoku puzzles per page. You can choose between four difficulty levels or let OpenSky randomly pick one for you.


Best Sites to Play Sudoku Online for Free

Creating Sudoku puzzles from scratch can get boring pretty fast, which is why it’s always a good idea to bookmark a couple of sites that let you play Sudoku online for free.

1. Sudoku Online

sudoku online

Sudoku Online is a simple website with free Sudoku puzzles in four levels of difficulty (easy, medium, hard, and very hard). You can either select a cell and fill it in by typing the desired number on your keyboard, or you can use the virtual numbers on the site and play with your mouse only.

Sudoku Online gives players an unlimited number of undos, the ability to restart the game with a single click, and the option to print the generated Sudoku puzzle on a sheet of paper. Unfortunately, the site isn’t optimized for mobile devices, so we can’t recommend it to mobile users who want to solve Sudoku puzzles while commuting or waiting in a line at a grocery store.

2. Web Sudoku

web sudoku

Web Sudoku is a straightforward online Sudoku game with a clean layout and multiple useful features. The site was created in June 2005 by Gideon Greenspan and Rachel Lee, and it quickly became one of the most popular Sudoku websites in the world.

The site is completely free, supported by the money its developers make by selling Web Sudoku Deluxe, the premium version for Windows or Mac costing $14.95, and Web Sudoku Ebooks, which offer a unique ability to create and print personalized books of puzzles.

Web Sudoku is also available as a mobile app for Android and iOS, but the website itself is well-optimized for mobile devices. Regardless of which version of Web Sudoku you choose, you can always select between four difficulty levels: easy, medium, hard, and evil. The last difficulty level is truly diabolic, and you should have a lot of practice under your belt before you even attempt it.

3. Sudoku Kingdom

sudoku kingdom

If you want to compare your Sudoku skills against players from around the world, Sudoku Kingdom is the right website for you, featuring global leaderboards and rewards for players that score 100 points or more.

Sudoku Kingdom offers daily Sudoku puzzles in four levels of difficulty. Unlike most other Sudoku websites featured in this article, Sudoku Kingdom doesn’t allow its players to generate as many puzzles as they want. Instead, Sudoku Kingdom encourages players to register and come back every day for a new puzzle. Once a week, Sudoku Kingdom publishes the solutions to puzzles from the week before.

4. 247 Sudoku

247 sudoku

247 Sudoku is an important member of 247 Games, one of the best resources for free games on the internet. Like all other online games from 247 Games, this version of Sudoku has appealing graphics, sound effects, and built-in guide for new players.

As a player, you simply select an empty square and select a tile to fill the square. You can also select a number on the board to highlight numbers and click the pencil icon to switch to note-taking mode. 247 Sudoku provides Sudoku puzzles in four difficulty levels, and the jumps between them are nicely balanced.

5. Sudoku Solver

free sudoku solver

Sudoku Solver can help you solve any Sudoku puzzle you ever come across. To use this handy tool, you simply copy the numbers from any Sudoku puzzle you can’t solve by yourself and click the large Solve Puzzle button. Instantly, Sudoku Solver will fill in all remaining squares, giving you the right solution.  

In addition to helping you solve challenging Sudoku puzzles, Sudoku Solver provides a number of printable sheets with Sudoku puzzles in five levels of difficulty. The printable sheets contain minimal branding and are very clean, so you can use them for virtually any purpose.  

6. Sudoku Menu

sudoku menu

From Sudoku puzzles for complete beginners to Sudoku puzzles intended for experienced players, Sudoku Menu has it all. The site has been translated into several different languages, and it runs surprisingly well on mobile devices.

Sudoku Menu goes beyond traditional Sudoku puzzles, offering two interesting modifications of Sudoku: diagonal and odd/even Sudoku. In diagonal Sudoku, your goal is to fill the grid with numbers so that each of the rows, columns, highlighted 3×3 sections, and both diagonals contain all of the digits from 1 to 9. In odd/even Sudoku, certain squares are highlighted, and the highlighted squares may contain only odd or only even numbers.


sudoku com

Thanks to its memorable domain name, has become one of the most popular websites with Sudoku puzzles on the internet. However, this site has a lot more to offer besides an attractive domain name. For starters, it has a clean, modern design that’s easy on the eyes and also easy on your data allowance. is available on Android and iOS as a polished app with daily Sudoku challenges, seasonal events, statistics, unlimited undos, color themes, auto-save functionality, highlighting of a row, column, and box related to the selected cell, eraser, and many other useful features. The web version isn’t nearly as feature-packed, but it gets the job done and is easy to use.


Sudoku is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids contain all of the numbers from 1 to 9. The puzzle starts with a partially completed grid, which players have to fill in using logic.

There are several websites that offer free Sudoku games online. Some popular choices are Web Sudoku,, and 247 Sudoku. These sites often feature various difficulty levels and may have additional tools to help you solve puzzles.

Yes, beginners can play Sudoku online for free. Websites like and Web Sudoku offer levels ranging from easy to expert, making them suitable for players of all skill levels, including beginners. They typically include instructions and hints that can help new players learn how to play.

Yes, there are numerous apps available for both Android and iOS devices where you can play Sudoku for free. These apps can be downloaded from the Google Play Store or Apple App Store. They often include features such as daily challenges and varying difficulty levels.

Many free online Sudoku sites and apps provide hints and help options. Some even offer tutorials, error-checking, and an option to highlight all instances of a specific number, making it easier for players, especially beginners, to learn the ropes.

Multilayer versions of Sudoku are less common but sites like LIVE Sudoku offer players the chance to compete against each other in real time. These platforms can be fun for those who enjoy the added challenge of playing against others.

Playing Sudoku online can provide additional benefits compared to playing on paper, like automatic error-checking, a variety of puzzle difficulties available at a click, saving puzzles to resume later, and competing against time or other players, all of which might not be possible on paper.

Yes, many online Sudoku sites offer time-limited challenges, where players can test their speed and accuracy under the pressure of a countdown. These timed challenges can add a competitive edge to your puzzle-solving experience.

Some websites like Web Sudoku provide the option to print Sudoku puzzles. Players who prefer solving on paper but enjoy the vast array of puzzles online can print them out and play offline at their convenience.

Some Sudoku websites and apps allow you to create an account to track your progress. They may keep statistics of the puzzles you’ve completed, the time taken to solve them, and your improvement over time.

From time to time, websites might host Sudoku tournaments for players to compete against one another. These might be special events, with some offering prizes for top solvers, adding a competitive and social element to the game.

While some free online Sudoku sites allow you to play without registering, others may require you to sign up to save your progress or to play in more advanced modes, such as competing against other players.

To improve your Sudoku skills, practice regularly, start with easier puzzles, and gradually increase the difficulty level. Utilize online tutorials, strategies, and tips, and use features such as pencil marks and hint options offered by online Sudoku platforms to assist you in solving more complex puzzles.

Some websites may allow you to create your own Sudoku puzzles to solve yourself or share with others. However, the feature is less common than pre-generated puzzles, so you may need to explore various sites to find this option.

You might encounter themed Sudoku puzzles on certain special occasions, such as holidays or events, where the visual design or the structure of the puzzle is adjusted to fit the theme. These are typically available on various Sudoku dedicated websites or apps.

Many online Sudoku platforms cater to an international audience, offering multiple language options. This is helpful for non-English speakers looking to solve puzzles in their native language.

Several websites and apps provide educational resources for learning Sudoku, including strategy guides, instructional videos, and forums where users can share techniques and ask for advice. These can be invaluable for both beginners and experienced players looking to sharpen their skills.

Some online platforms may offer the option to play against friends, or at least compare your times and scores with them, making Sudoku a more socially engaging experience.

Online Sudoku games can typically be played on a variety of devices, such as desktop computers, laptops, tablets, and smartphones. Most websites are mobile-friendly, and there are apps specifically designed for mobile devices.

To protect your privacy, choose Sudoku websites that have secure connections (HTTPS), read their privacy policies, and be cautious with the personal information you provide when registering. If an account is not necessary, consider playing without creating one.