Play Sudoku Free.
Climb the Leaderboard.
Unlimited free puzzles across 9×9 Classic (six tiers from Easy to Evil), 6×6 Mini, 4×4 Kids, and the cage-based Killer Sudoku variant. Earn XP, level up, race friends on the same board. Sign in free to go ad-free and save your progress across devices — or jump in as a guest and start solving in seconds.
Track your streak, earn XP, climb the leaderboard, and challenge friends.
Start Playing FreeWant a fresh puzzle every day? Play the free daily sudoku.
Join the sudoku community
Free for everyone — no credit card, no email required. Pick a character, save your progress across devices, and climb the leaderboard.
All-time top players
All-TimeOne click with Google. No password, no card, no spam.
View full leaderboard →Unlimited puzzles across every mode
Classic 9×9 across six difficulty tiers (Easy → Medium → Hard → Expert → Master → Evil), plus 6×6 Mini, 4×4 Kids, and the cage-based Killer Sudoku variant. Every puzzle is mathematically unique and logic-solvable — no guessing, no downloads, no paywall.
Earn XP and level up
Every solve awards XP, with tougher difficulties paying more and a bonus for winning challenges. Master and Evil pay the most; Killer Sudoku counts toward the same XP ladder.
Build a daily streak
Solve one puzzle a day and your streak grows. Miss a day and it resets to 1. The flame next to your avatar tracks your consistency — keep it burning to climb the weekly leaderboard.
What's new
Three big upgrades, all live now
Killer Sudoku
Cages with target sums replace givens. Every digit in a cage is distinct and adds up to the cage total — the sudoku.com #2 mode, now on Sudoku247Online across four difficulty tiers.
Try Killer →New tierMaster & Evil
Two new difficulty tiers above Expert. Master sits at 18-19 givens with advanced technique territory; Evil ships at the proven 17-given floor for a real cognitive workout.
Climb the ladder →New controlShow Candidates + smarter hints
One tap fills every empty cell with its valid pencil marks. A new graduated hint menu offers Reveal Cell (1 hint), Reveal Box (3 hints), or free Show Candidates — every action is undoable.
Solve smarter →How to Play
Fill the Rows
Each row must contain every digit from 1 to 9 without any repetition.
Complete Columns
Every vertical column must also house all numbers from 1 through 9 once.
Solve the Box
Each of the nine 3x3 sub-grids must satisfy the same unique digit rule.
Ready for real techniques?
Once the basics click, named patterns do the heavy lifting. The wiki's encyclopedia explains 25 solving techniques — from Naked Singles to Forcing Chains — with diagrams and worked examples for each.
Explore the sudoku technique encyclopedia →Take your logic to the tactile world.
Unlimited free printable sudoku — any grid size, any difficulty, 1 / 4 / 6 per page. No watermarks, no sign-up, no email.
Print Today's Puzzle
Sign in free. Lose the ads. Keep the progress.
Creating an account takes one tap. In return you get a fully ad-free experience, XP and levels that stick, cross-device sync, a global leaderboard, 1-vs-1 challenges with friends, and direct support when you need it. No email, no password, no credit card — ever.
Zero ads — signed-in only
Guests see sponsored banners; signed-in users get every page ad-free — board, leaderboard, print hub, everywhere.
Global leaderboard
All-Time and Last-7-Days tabs, ranked by XP, with country flags. Your row is highlighted when you're on it.
Friends by email
Send a friend request to any email address. If they already play, they get an in-app request. If not, we queue an invite for when they join.
1-vs-1 challenges
Pick a friend, pick a difficulty, both race on the exact same puzzle. Fastest finisher earns a bonus on top of the regular solve reward.
Direct support — new
Bug, missing streak, or a question? Open a ticket from the new Support page in your account menu. Replies typically within 24 hours.
One click with Google. No password, no card, no spam.
Strategy, tips and guides
Sudoku Cheat Sheet: A Quick Guide to Every Technique
This Sudoku cheat sheet lays out every solving technique at a glance, from naked singles to X-Wing and forcing chains. Find the right move for any puzzle.
What is the Hardest Sudoku Puzzle Ever Made?
What is the hardest Sudoku ever made? Meet AI Escargot by Arto Inkala, why it scores 11 of 11, and how the world’s toughest puzzles are really measured.
How to Solve Sudoku Faster: Tips to Improve Your Speed
Learn how to solve Sudoku faster with 7 proven tips: scan by number, spot patterns instantly, track candidates cleanly, and cut backtracking. Build real speed.