16×16 Sudoku
A 256-cell grid with more candidates to organise.
Stuck, or just getting started? Let’s practise ↓
No repeats in any row, column or box
Take a breather
Your game will be here when you return
Tap to note, again to eliminate, and once more to restore
Use 1–9 to enter numbers
and arrow keys to select a cell
Your journey
Finish each stage to unlock the next
PLAY · NOTICE · TRY
One small move at a time.
Pick a step below. You can try, get it wrong and start again. Your saved game stays here.
Start with the row, column or box that has the most numbers
Fewer empty cells can make the next answer easier to spot
16×16 Sudoku — rules and practice
Every row, column and 4×4 box must contain each value from 1–16 once. The no-repeat rule is unchanged, but you have more cells to inspect. Sudoku-Y displays numbers rather than letter symbols on the board, including the values 10–16.
A two-digit value still occupies one cell
10 and 16 are each one value, not two entries sharing a cell. Check what is missing from the set 1–16. If a row already contains 1 through 14 and 16, it is missing 15. Classic Sudoku does not require addition to find this placement.
Organise notes before filling the board
Start with nearly complete units, then record candidates that cannot yet be ruled out. Notes appear smaller on this larger grid. Selecting an empty cell with notes also shows its candidate list beside the controls, helping you read the possibilities without scrolling inside the board.
Use the keyboard for larger values
Keys 1–9 enter those digits. A, B, C, D, E, F and G enter 10, 11, 12, 13, 14, 15 and 16 respectively. You can also use the on-screen number pad. Larger puzzles can take a little longer to prepare. Wait for the board to appear before entering a value.
Try a small example
A sample row already has 1 through 14 and 16. What is its final value?
Show reasoning
15, the only missing member of 1–16. The example abbreviates 1 through 14 as a range for readability; it is not a full puzzle.
Common questions
Does the board scroll internally?
No. It fits the screen width, with the 16×16 controls below the board. On small screens, use the selected-cell note summary to read candidates.
Is every 16×16 puzzle harder than 9×9?
No. Size adds scanning work, while logical difficulty also depends on the puzzle. Compare your results within the same size and difficulty setting.