20–24 clues · typical solve 40 minutes to over an hour
Printable expert sudoku puzzles — the hardest free PDF grids
Stripped to the bone — around a quarter of the grid filled in, and a single solution waiting at the end of it.
Set an expert run
difficulty is already set to expert — adjust the rest
1–60 · each puzzle is solver-checked for a single solution before it goes in
This is a live sample puzzle — it updates to your own puzzles once the run finishes.
What a expert sudoku asks of you
Expert puzzles carry 20 to 24 clues, which is close to the floor for a sudoku that still has one answer. The theoretical minimum is 17, and puzzles at that count are rare enough to be catalogued individually; at 20 to 24 the generator can reliably produce grids that are brutally sparse and still perfectly sound. What that means in practice is that the first ten minutes may yield nothing at all beyond a fully pencilled board.
From there it is chains and eliminations. X-wings, unique rectangles, forcing chains — the techniques that only pay off when there is nothing simpler left to try. Many solvers work these puzzles over several sittings, and there is no shame in that. An expert grid is not a test of speed; it is a test of whether you can keep a board consistent in your head, and on paper, for an hour.
Two warnings worth taking seriously. First, print one per page — you will need every millimetre for candidate marks, and a cramped grid will lose you the puzzle to a misread digit rather than to the logic. Second, print the answer key. On a puzzle this sparse, a single wrong entry early on can survive for forty moves before the contradiction surfaces, and being able to check a finished grid is the difference between satisfaction and an evening wasted.
Printable expert sudoku — questions
How many clues does an expert sudoku have?
Between 20 and 24. For comparison, an easy puzzle starts with 38 to 45 — so an expert grid asks you to work out nearly three quarters of the board from a quarter of it.
What is the minimum number of clues a sudoku can have?
Seventeen. It was proved in 2012 that no valid sudoku with a unique solution can have sixteen or fewer clues. Our expert range sits a little above that floor because puzzles at 17 clues are extremely rare and cannot be produced reliably on demand.
Are expert puzzles still solvable without guessing?
Yes. Every puzzle here is verified to have exactly one solution, and a unique solution is always reachable by logic. It may take advanced techniques and a lot of patience, but there is a deduction available at every stage.
Why do expert puzzles take longer to generate?
Because each clue removal is tested. To get down to 22 clues the generator has to try removing far more cells than it keeps removed, running the solver every time to check the puzzle still has one answer. A batch of expert puzzles does more work per puzzle than a batch of easy ones.
Try another level
Expert is as far as the generator goes. If these are taking longer than you would like, drop back a level — the logic is the same, there is just more of it on the page already.
- Printable sudoku — easy38–45 cluesGenerous clue counts, no guessing, and a solving path that opens up the moment you start scanning.typical solve: 5–10 minutes
- Printable sudoku — medium30–37 cluesThe everyday sudoku — the level a newspaper prints on a Wednesday.typical solve: 10–20 minutes
- Printable sudoku — hard25–29 cluesSparse grids that will not open up until you start reasoning about where digits cannot go.typical solve: 20–40 minutes
Or head back to the free printable sudoku generator for a mixed run, or take a set of printable sudoku with answers.