Yes. Sudoku.com is free to play in your browser and on mobile, supported by ads. There is an optional paid tier that removes ads and unlocks a few extra features, but every difficulty level and the daily challenge are available without paying.

What's the best free online Sudoku?

It depends on what you want. Sudoku.com has the most polished interface and daily challenges. Web Sudoku is the most minimal and has been running since 2005. The New York Times offers high-quality hand-checked puzzles but paywalls the harder difficulties. Cosmic Sudoku on Vibe Arcade offers four difficulty tiers, pencil marks, and a per-difficulty leaderboard with no account required.

What's the difference between Sudoku and Killer Sudoku?

Killer Sudoku uses the same 9x9 grid and the same row, column, and box rules as classic Sudoku. The difference is that it starts with no given numbers. Instead, the grid is divided into dashed 'cages', and each cage shows a sum. You have to place digits so that every cage adds up to its target, with no repeats inside a cage. It combines Sudoku logic with arithmetic.

Can you solve Sudoku without guessing?

Every well-formed Sudoku puzzle has exactly one solution and can be solved by pure deduction. Easy and medium puzzles use techniques like naked singles, hidden singles, and pointing pairs. Harder puzzles require chains and colouring techniques. Puzzles labelled 'evil' or 'diabolical' on some sites may demand advanced techniques, but they are still logically solvable without guessing.

Are there Sudoku variants?

Yes, many. Killer Sudoku adds cage sums. Samurai Sudoku combines five overlapping 9x9 grids. Sudoku X adds a uniqueness constraint on both diagonals. Hyper Sudoku adds four extra 3x3 regions. Kakuro is a close cousin that blends Sudoku with crosswords using arithmetic clues. Nonograms use a different mechanic but exercise the same logical-deduction skills.

Games Like Sudoku: Best Free Logic Number Puzzles

Q: Who invented Sudoku?

The modern puzzle was designed by retired American architect Howard Garns in 1979, published as 'Number Place' in Dell magazines. Japanese publisher Nikoli picked it up in 1984 and renamed it Sudoku. Its roots go back further to Latin squares, formally studied by the Swiss mathematician Leonhard Euler in the 18th century.

April 18, 2026 · By the Vibe Arcade Team · 9 min read

Sudoku's roots trace back to Latin squares, a combinatorial object formally studied by Leonhard Euler in the 18th century. The modern puzzle was invented in 1979 by retired American architect Howard Garns and published as "Number Place" in Dell magazines. Japanese publisher Nikoli picked it up in 1984 and renamed it Sudoku — short for a phrase that roughly means "the digits must be single". It spent another two decades as a niche hobby until The Times of London ran its first Sudoku in 2004, which triggered a global craze.

Today the audience is enormous, and there are more Sudoku sites, apps, and variants than any one player could ever work through. Here's a genuine roundup of free games worth trying if you already love Sudoku.

What Makes a Sudoku-Like

The category is tighter than you might think. A true Sudoku-like has a grid with overlapping constraint rules — usually rows, columns, and regions — and a solution path that rewards logical deduction rather than guessing. Every clue you place should follow from the clues already there.

The best implementations get the small things right. Difficulty is controlled by clue density and which techniques are required to reach the solution, not by making the grid bigger. Pencil-mark support lets you jot down candidates in a cell before committing. Error checking is usually optional, because some players prefer to catch their own mistakes. And the puzzle generator should guarantee a unique solution — two valid answers means the puzzle is broken.

1. Sudoku.com

Sudoku.com is the default recommendation for a reason. It's free with ads, works on desktop and mobile, and has a clean touch-friendly interface. There are four difficulty tiers, a daily challenge that's the same for everyone, and the usual pencil-mark and error-checking toggles. Puzzles are machine-generated but well-tuned — the easy ones really are solvable by simple elimination, and the expert tier genuinely demands advanced techniques.

If you just want to play Sudoku right now with no friction, start here.

2. NYT Sudoku

The New York Times Sudoku section at nytimes.com/puzzles/sudoku offers easy, medium, and hard puzzles each day. The presentation is minimal and beautifully typeset, and the puzzles are curated rather than purely algorithmic. The easy puzzle is free; medium and hard sit behind the Games subscription.

If you already have a Times subscription for the crossword or Wordle, the Sudoku comes with it. If not, the free daily easy puzzle is still worth your time.

3. Web Sudoku

Web Sudoku has been running at websudoku.com since 2005 and looks almost exactly like it did then. The interface is deliberately minimal: pick easy, medium, hard, or evil, and you're dropped into a numbered grid. No account, no daily streak, no coins. Every puzzle has a unique ID you can share, and there's a "show candidates" option if you want built-in pencil marks.

It feels like a relic of an older web, and that's exactly why people still use it.

4. Cosmic Sudoku

Cosmic Sudoku is our take on the format. You get four difficulty tiers, pencil marks, auto-check, and a per-difficulty leaderboard ranked by solve time — so your expert times aren't competing with someone's easy run. The aesthetic is neon rather than newsprint, but the puzzle logic underneath is the same classical 9x9 with row, column, and box constraints.

No account required, no installs, no ads mid-puzzle. Just open it and start solving.

5. Sudoku Kingdom

Sudoku Kingdom is another long-running free Sudoku site. It has five difficulty tiers, a printable version for people who still prefer paper and pencil, and an archive you can browse by date. The interface is dated but functional, and the puzzle quality is solid.

It's the kind of site you bookmark and forget about, then come back to a year later to find it still works exactly the same way.

6. Killer Sudoku

Killer Sudoku is the most popular Sudoku variant. You get a standard 9x9 grid with the usual row, column, and box rules, but the grid starts with no given numbers. Instead, it's divided into irregular "cages" marked with dashed borders, and each cage has a target sum printed in the corner. The digits in a cage must add to that sum with no repeats.

The result is a puzzle that uses Sudoku deduction plus arithmetic. Free versions are available at sites like Sudoku.com, Krazydad, and dedicated Killer Sudoku apps.

7. Samurai Sudoku

Samurai Sudoku stitches five 9x9 grids together in a cross pattern, with the four corner grids sharing a box with the central grid. You solve all five simultaneously, and the overlapping boxes mean progress in one grid unlocks progress in the others. The total playfield is 21x21.

It's a lot of puzzle. A single Samurai grid can take an hour or more, which is either a feature or a bug depending on your schedule. Krazydad hosts a large free archive.

8. Sudoku X and Hyper Sudoku

Sudoku X adds a uniqueness constraint to both main diagonals of the 9x9 grid — every digit from 1 to 9 must appear exactly once on each diagonal, in addition to the standard row, column, and box rules. Hyper Sudoku overlays four additional 3x3 regions on top of the standard grid. Both variants feel like classical Sudoku at first glance but demand that you track extra constraints. Free versions are widely available on Sudoku.com and specialised variant sites.

9. Kakuro

Kakuro is Sudoku's crossword cousin. The grid looks like a crossword, with black squares and numbered clues, except the clues are sums instead of words. Each row and column of white cells must add up to the clue at its start, with digits 1-9 and no repeats inside a single run.

The deduction style is different from Sudoku — you're working with combinations and sum constraints rather than row/column/box exclusion — but it exercises the same puzzle-solving muscle. Kakuros.com and Conceptis Puzzles both offer free Kakuros online.

10. Nonograms and Picross

Nonograms (also called Picross or Griddlers) use a grid of clues along the rows and columns that tell you how many cells in each line must be filled. Solve the constraints and a pixel-art picture emerges. It's a different genre from Sudoku, but the underlying skill — constraint satisfaction by logical deduction — is the same.

If you love the "I can prove this cell must be X" moment in Sudoku, nonograms deliver that feeling repeatedly. Free versions are available at Nonograms.org and in the Picross app ecosystem.

Picking a Favourite

If you're new to variants, start with Killer Sudoku. It's the closest cousin to classic Sudoku and the one that most Sudoku players take to quickly. From there, Kakuro is the natural next step if you enjoyed the arithmetic layer, and Samurai is the one to try if you want pure classical Sudoku at a larger scale.

For everyday play, Sudoku.com and Cosmic Sudoku are both polished modern options. Web Sudoku is the minimalist classic. The NYT is the curated option. And if Sudoku ever starts to feel repetitive, nonograms are a genuinely different puzzle that scratches the same logical itch.

Want to try our take? Cosmic Sudoku has four difficulty tiers, pencil marks, and a per-difficulty leaderboard. Free, no account, runs in your browser.