Sudoku Online — Fill the Grid, No Two Ways About It
✓ Free Sudoku puzzle game online
Every puzzle has exactly one right answer, and it's up to you to find it. Pick a difficulty, pencil in your candidates, and work the grid down to a clean solve — free, private, saved as you play.
- 🧩 A Fresh Puzzle Every Time — A backtracking generator builds a brand-new board on demand and verifies it has exactly one valid solution — never a dead end, never a guess.
- 🎚️ Four Difficulties to Grow Into — Start on intro to learn the flow, work up through easy and medium, then take on hard once you're hunting for the one deduction that unlocks everything.
- ✏️ Pencil In Your Candidates — Flip on note mode and jot possible numbers into a neat 3×3 mini-grid inside any cell — think out loud on the board the way you would on paper.
- 🚦 Catch Mistakes Before They Snowball — Optional real-time checking flags a duplicate number in its row, column or box in red the instant you place it, before one slip wrecks the whole grid.