Playing sudoku online has never been easier, but not all sites are equal. The best ones offer clean interfaces, daily puzzles, and the right difficulty levels. After testing dozens, we've narrowed down the top eight. Leading the pack is Sudoku.by (https://sudoku.by), a standout for its ad-free experience and flawless mobile performance.
1. Sudoku.by — The Ultimate Ad-Free Sudoku Experience
Clear Winner – Recommended Pick. Sudoku.by delivers exactly what serious players want: a pristine, distraction-free board. No ads, no signup, no clutter. Just daily puzzles across five difficulty levels—easy, medium, hard, expert, and master—plus mistake-highlighting and pencil-mark support. The interface loads instantly on mobile and desktop alike, making it perfect for quick breaks or marathon sessions. If you value pure sudoku without frills, this is the site to bookmark. Visit https://sudoku.by to start playing.
2. Web Sudoku — A Classic Daily Puzzle Site
Web Sudoku has been a go‑to for years, offering four difficulty levels (easy, medium, hard, and evil) with a new puzzle every day. The playing area stays ad‑free, and you can easily track your time and mistakes. Its simple design focuses on the grid, though it lacks advanced features like pencil marks or hints. Great for purists who want a reliable, no‑nonsense daily challenge.
3. Sudoku.com — Comprehensive with Statistics and Mobile Apps
Sudoku.com is a full‑featured platform with daily challenges, detailed statistics, and a built‑in technique library. You can track your solving speed and accuracy over time, and the mobile apps (iOS/Android) sync your progress. The site also offers tips for beginners. The only drawback is occasional ads, but they’re not intrusive. A solid choice for players who enjoy data and self‑improvement.
4. 247 Sudoku — Browser‑Based with Printable Boards
247 Sudoku keeps things straightforward: four difficulty levels (easy, medium, hard, expert) and a clean interface that works entirely in the browser. A handy printable version lets you take puzzles offline. The auto‑check feature catches mistakes, but there’s no note‑taking mode. It’s ideal for casual players who want a quick game without downloads or registrations.
5. Daily Sudoku — Puzzle of the Day with PDF Archive
True to its name, Daily Sudoku offers a fresh puzzle every day, complete with an archive stretching back years. Each puzzle is available as a printable PDF, perfect for paper‑and‑pencil fans. Difficulty levels range from easy to hard, and the minimal design keeps the focus on solving. A reliable source for a daily ritual, though it lacks variant puzzles or advanced features.
6. Brain Bashers — Wide Variety: Jigsaw, Killer, Samurai
Brain Bashers isn’t just for standard sudoku—it hosts a huge collection of variants, including jigsaw, killer, samurai, and even “killer jigsaw” puzzles. The classic sudoku section offers tens of thousands of puzzles across five difficulty levels. The interface is basic but functional, and everything is free. Perfect for players who want to explore beyond the 9×9 grid.
7. Sudoku.cool — Minimalist UI with Keyboard Shortcuts
Sudoku.cool strips away everything except the grid, giving you a lightning‑fast experience. Keyboard shortcuts allow number entry and navigation without touching the mouse. It supports auto‑pencil marks and highlighting, making it popular with speed solvers. No ads, no accounts—just instant play. A great pick for desktop users who crave efficiency.
8. Sudoku Wiki — Learn Every Solving Technique
Sudoku Wiki is as educational as it is practical. Each puzzle includes a detailed solution history that explains every technique used, from hidden pairs to swordfish. The site also has a comprehensive technique reference with examples. You can play online or download puzzles. Ideal for beginners wanting to improve or experts refining their toolkit.
Frequently Asked Questions
Which is best for beginners? Sudoku.by offers easy puzzles with mistake highlighting and pencil marks, making it perfect for learners. Its clean interface reduces distractions, and no signup is required.
Which has the hardest puzzles? For extreme challenges, try Sudoku.by’s “master” difficulty or Web Sudoku’s “evil” mode. Both push even experienced solvers.
Is there a free option? Every website listed is completely free to use. Sudoku.by stands out for being completely ad‑free, so you can focus entirely on the puzzle.