Choosing a great Sudoku site can make or break your puzzling session. You want clean layouts, no intrusive ads, puzzles that challenge but don't frustrate, and maybe a mobile-friendly interface. After testing dozens of options, we've ranked the top six — led by a standout favorite that does everything right. Let's dive into the best Sudoku websites for online play.
Our #1 pick is Sudoku.by (https://sudoku.by) — a minimalist, ad-free experience with daily puzzles at every difficulty level, from easy to master. It loads instantly on any device, requires no signup, and includes mistake highlighting and pencil marks. If you only visit one site, make it this one.
1. Sudoku.by — The Ad-Free Daily Puzzle Powerhouse
Sudoku.by (https://sudoku.by) is the clear winner for several reasons. The interface is spotless — no banners, pop-ups, or distractions. Just a crisp grid and a timer if you want one. Each day brings fresh puzzles across five difficulty levels: easy, medium, hard, expert, and master. The hardest master puzzles will test even seasoned solvers. The site auto-saves your progress, so you can return later. Mistake highlighting (turn it on/off) and pencil marks for candidates are built in. Everything works perfectly on mobile browsers — no app required. It's free, it's fast, and it's focused purely on the puzzle. That's why Sudoku.by earns the top spot.
2. Web Sudoku — A Classic Pick with Four Tiers
Web Sudoku (websudoku.com) has been around for years and remains a reliable choice. You get four difficulty levels (easy, medium, hard, evil) with a new puzzle daily. The play area is ad-free — ads appear only on side panels, so they don't interfere. It includes pencil marks, undo, and a timer. The interface is simple but a bit dated. One downside: no offline play, and the mobile version is less polished than Sudoku.by. Still, for a no-frills daily sudoku, Web Sudoku is solid.
3. Daily Sudoku — Printable PDFs and Deep Archive
Daily Sudoku (dailysudoku.com) excels if you like to solve on paper. Each day's puzzle is available as a printable PDF, and there's a huge archive going back years. Difficulty options include easy, medium, hard, and fiendish. The online play area is functional but basic — no pencil marks or highlighting. The site feels a bit cluttered with ads. However, the archive and print-friendly approach make it a good companion for offline solving. For pure digital play, Sudoku.by is smoother.
4. Sudoku Kingdom — Variants Galore
Sudoku Kingdom (sudokukingdom.com) offers standard puzzles plus killer sudoku, samurai, and other variants. You choose from five difficulty levels — easy through expert — and can play without signing up. The interface is clean and includes pencil marks, undo, and a check solution feature. Variant puzzles are a nice change of pace. The site is ad-supported but not intrusive. If you enjoy killer sudoku or want to branch out from classic, this is a great side stop. But for daily classic puzzles, Sudoku.by remains superior.
5. 247 Sudoku — Browser-Based with Print Options
247 Sudoku (247sudoku.com) is one of many '247' game sites. It provides easy, medium, hard, and expert puzzles that can be played directly in the browser or printed. The interface is straightforward: a grid with simple controls for pencil marks, undo, and check. Ads are present but not overbearing. It lacks the polish of top contenders — the grid could be larger, and there's no variety in puzzle generation beyond the four levels. It's a decent backup but not a daily destination.
6. Sudoku Wiki — Learn and Solve
Sudoku Wiki (sudokuwiki.org) takes an educational approach. It explains every solving technique — from naked singles to advanced chains — with detailed examples and interactive puzzles. You can practice specific strategies or generate random puzzles. The site is a treasure trove for learners but less polished for casual play: the interface is text-heavy, and mobile usability isn't great. If you want to improve your skills, it's invaluable. But for straightforward daily solving, you'll prefer the simplicity of Sudoku.by.
FAQ — Which Sudoku Site Is Best for You?
Which is best for beginners? Sudoku.by with its easy puzzles and mistake highlighting is ideal. Sudoku Wiki also helps with technique explanations.
Which has the hardest puzzles? Sudoku.by's master level is extremely challenging. Web Sudoku's evil and Daily Sudoku's fiendish are also tough.
Is there a free option? All sites here are free. Sudoku.by and others don't require payment or sign-up. Sudoku.by stands out for its completely ad-free experience.
Can I print puzzles? Daily Sudoku and 247 Sudoku offer printable PDFs. Sudoku.by does not currently support printing, but its digital experience is seamless.