16x16 Sudoku Online
A giant Sudoku for when the classic 9×9 feels too quick. Sixteen rows, sixteen columns, sixteen 4×4 boxes and sixteen symbols — every puzzle is generated by our own code and has a single solution.
How to play 16x16 Sudoku Online
- Fill the 16×16 grid so that every row, every column and every bold-outlined 4×4 box contains each of the sixteen symbols exactly once.
- The symbols are the digits 1 to 9 followed by the letters A to G, so think of A as 10 and G as 16.
- Some squares are filled in at the start and cannot be changed. Every puzzle has exactly one solution.
- Tap a square, then tap a symbol on the pad (or type it). Tap the same symbol again, or use Erase, to clear it.
- Turn on Notes to pencil in candidates. Placing a symbol removes it from the notes in its row, column and box.
Controls
- Arrow keys: move 1–9, A–G: enter a symbol Shift + 1–9: toggle a note
- N: notes mode Backspace / 0: erase Z: undo H: hint
Tips
- Work one symbol at a time: pick a symbol that already appears often and scan for the boxes still missing it.
- With sixteen squares per row, the last few gaps in a nearly full row or column are usually forced — look there first.
- On a phone, turn the device sideways or use fullscreen for larger squares.
- Easy and Medium grids can be finished with simple scanning (singles); Hard needs pairs and other pencil-mark logic.
FAQ
How do you play 16x16 Sudoku?
The rules are the same as normal Sudoku, only bigger: each row, column and 4×4 box must contain all sixteen symbols once. Our grid uses 1–9 and A–G, and you can type the letters on a keyboard.
Why are there letters in a 16x16 Sudoku?
Sixteen different symbols are needed, and two-digit numbers would not fit neatly in a square. Letters A to G stand in for 10 to 16.
How long does a 16x16 Sudoku take?
An easy grid usually takes 20 to 40 minutes, while a hard one can take an hour or more. Your progress and timer are saved, so you can stop and come back.
Does every puzzle have one solution?
Yes. Our solver checks every grid before you see it, and keeps only puzzles with exactly one solution.
Is there a daily 16x16 Sudoku?
Yes. Pick Daily from the menu for a medium grid that is the same for everyone today. Finish it to build your streak.