What makes Expert so tough?
Expert 16×16 Sudoku starts with fewer filled cells than the other 16×16 levels. The number set and 4×4 boxes stay the same, so you can build on the techniques you used on Hard.
Each puzzle has one solution. Use notes to track what could fit, and make a placement when you can explain why that number belongs there. Hints are available whenever you need help.
For more practice, try Hard 16×16 Sudoku first; the techniques are exactly the same, just with more starter numbers to lean on.
Techniques worth memorising
- 🔢 Hidden singles in every row, column and box — scan every time you place a new number
- 🔢 Naked pairs: two cells in one row, column or box with exactly the same two candidates reserve those numbers for that pair
- 🔢 Naked triples: three cells in one row, column or box whose candidates together contain only three numbers reserve those numbers for those cells
- 🔢 Box-to-line clues: if all possible places for a number in a box lie in one row or column, remove that candidate from the rest of that row or column outside the box
- 🔢 Cross-hatching: pick one number, find every box it could be in, work out where it has to go
Expert solving routine
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Auto Notes first
Tap it the moment the puzzle loads. You will see every candidate number at a glance.
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Sweep one number at a time
Pick a number — say 15. Find every box where it could go. Lock in any forced placements.
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Scan every region after every move
After every single placement, glance at the row, column and box you just affected. Hidden singles appear all the time.
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Hunt naked pairs and triples
After Auto Notes, look for two cells with the exact same two candidates on any row, column or box — those numbers are locked there.
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Place, repeat, win
Each placement narrows things down everywhere. Keep going until the board is full!
When you have mastered Expert
Once Expert 16×16 Sudoku feels comfortable, try our toughest Expert 9×9 sudoku. It is a different kind of challenge — a smaller board with tougher patterns — and the same long-thinking patience pays off.
Or try X-Sudoku for puzzles with two diagonals, Killer Sudoku for puzzles with cage sums, or Jigsaw Sudoku for puzzles with wiggly regions instead of normal boxes.
Frequently asked questions
How long does an Expert 16×16 take?
Allow time for a longer puzzle and work at your own pace. Your experience, the starting clues and the tools you use all affect the time. There is no time limit.
Does an Expert 16×16 puzzle have one solution?
Yes. The generator checks that each puzzle has exactly one solution. Use notes to explore possible placements, Check to review your entries and Hint if you need a correct number to continue.
What if I am really stuck?
Tap the Hint button — it fills one correct cell so you can keep going. Hints count in your stats, but they are there to help.
Is Expert the hardest 16×16 level?
Yes — Expert is the highest of our four 16×16 difficulty levels. For a different challenge, try another sudoku variant or return to a smaller grid at Expert difficulty.
Try other sudoku games
Different rules, same friendly board. Pick a sibling puzzle to play next.