Sudoku Puzzles

Most Sudoku sites label puzzles simply as easy, medium, or hard — but those labels mean different things everywhere. We measure every puzzle with the Sudoku Explainer rating (SE), the standard objective scale used by the Sudoku community. The rating of a puzzle equals the difficulty of the hardest technique required to solve it logically: a puzzle solved with singles alone scores around 1.2, while one that demands forcing chains scores 7.x or higher.

The scale runs from SE 1.0 (pure singles) up to SE 9.x+ for the hardest known human-solvable puzzles. Because each band corresponds to real solving techniques — not a gut feeling — you always know exactly what a puzzle will demand from you. If a technique name is unfamiliar, the Sudoku FAQ explains each one step by step.

Our library spans SE 1.2 to SE 8.x. Easy Sudoku and Medium Sudoku puzzles live in the 1.x band and are solved by singles; Hard Sudoku reaches into 2.x–3.0 where pairs, pointing and box-line reductions appear; Expert Sudoku goes further with X-Wings and hidden subsets. The Master Sudoku tier is where the rating system really shines: five sub-levels — Young (4.x), Adept (5.x), Veteran (6.x), Fiendish (7.x) and Supreme (8.x) — each demanding progressively deeper chains and pattern recognition.

Use the difficulty spectrum above to jump straight to the level you want and start playing instantly — or play free Sudoku online right now.

Preset levels too coarse? The precision generator above accepts any SE rating from 1.0 to 9.0 in steps of 0.1. Dial in 4.3, 5.7 or 7.9 and we craft a fresh puzzle that demands exactly that level of technique — far finer control than easy/medium/hard labels ever give.

And you'll never reach the end of the collection: there are roughly 6.67 × 10²¹ valid completed Sudoku grids — about 6.7 sextillion. New puzzles are generated across the whole rating range, so the supply at your exact difficulty is effectively unlimited.

An objective rating removes the guesswork: beginners aren't thrown into a puzzle that secretly requires advanced techniques, and experienced players can be sure a 7.x Fiendish puzzle will genuinely test them. It's also the fairest way to compare solving times — your Sudoku statistics show real progress, and moving from 3.x to 5.x puzzles is a measurable skill jump, not just a harder label.