About 16×16 Hard Sudoku

A 16×16 Sudoku uses numbers 1–16 and sixteen 4×4 boxes. Only for seasoned puzzle solvers.

At Hard difficulty, 30% of the 256 cells are pre-filled, leaving 179 cells for you to solve. Requires careful technique and pencil marks.

Tip: Use the Notes feature to pencil in candidates for each empty cell before committing.

Other difficulty levels for 16×16

How many hard 16×16 Sudoku puzzles are available?

Unlimited. Every time you click "New Game" a brand-new algorithmically generated puzzle is created. You will never run out of puzzles.

Are these puzzles printable?

Yes! Visit our printable Sudoku page to generate 4 puzzles per page as a PDF. Free, no login needed.

What solving techniques does Hard difficulty require?

Naked/hidden pairs, pointing pairs, and advanced elimination.

Free, instant, no login — works on mobile, tablet and desktop.