Online sudoku, but live and free to play: share a six-character room code, watch your friends' moves land in real time, and finish one grid as a team — or keep a quiet solo board for yourself.
Puzzle #47 · Hard
Pick a difficulty and a mode. Every puzzle is generated fresh with a single valid solution.
Friends punch in your six-character code, you wave them in, and everyone gets a color.
One shared grid, live cursors, every move checked by the server. The room erupts when the last cell lands.
Five difficulties from easy to extreme. Pencil notes, auto-notes, hints and best times. Your board saves itself — close the tab, come back tomorrow.
START A PUZZLECo-op on one shared grid. See where everyone's working, fix each other's slips, finish as a team. Rooms survive a dropped connection.
How sudoku with friends works →Same puzzle, your own board. Watch how far your rivals have got and be the first to finish. No hints, just solving.
Start a battleA solver checks every grid before you see it, so there's always a logical way forward. Stuck? A hint can prove the next step.
Stuck? A hint doesn't just fill in a cell. It shows the proof, step by step, so next time you can spot it yourself.
Stuck on a puzzle from a newspaper or another app? Take a photo, and the solver walks you through it the same way, one step at a time.
TRY THE SUDOKU SOLVER →The whole rulebook in two minutes: one rule, the givens, your first forced cell, and how difficulties actually differ.
READ THE RULES →Scanning, naked and hidden singles, pencil-mark discipline — the four moves every sudoku starts with, and a guide for each harder pattern.
LEVEL UP →Solo works instantly, no account needed. Only the player who opens a room signs in with Google; friends tap the invite link and join as guests, no account. Signing in also keeps your save on every device.
It's free to play — open the site and start. Every mode, every difficulty, no download or install.
Create a room, send the six-character code, approve whoever knocks. Everyone plays the same grid live from their own browser.
Not for solo, and not to join a friend's room: the invite link lets anyone in as a guest with just a nickname. Only opening a room takes a Google sign-in, so rooms know who's who and your progress can follow you between devices.
It's a website — phone, tablet, laptop, whatever's nearby. Nothing to install, nothing to update.
No. Every hint explains itself: which numbers are ruled out and why, the technique it uses (like a pointing pair) and, when nothing simpler works, a proof by contradiction. You learn how to find the number, not just what it is.
By the hardest technique it takes to solve, not by how many cells are empty — the way the best-known solving tools rate puzzles too. Easy needs only the simplest moves, Medium every kind of single, Hard pairs and pointing, Expert patterns like the X-Wing, and Extreme chains. Our grader solves every puzzle before you see it, so the label matches the work, and we check its grades against Sudoku Explainer's published ratings.