The 16x16 sudoku, sometimes called hexadoku or super sudoku, uses the symbols 1 to 9 and A to G (A stands for 10, G for 16). Every grid on this page is generated for you and checked by the 16x16 sudoku solver for a single answer and a difficulty rating.
Rules
Fill the 16 by 16 grid so that each row, each column and each 4 by 4 box contains each of the sixteen symbols once. Select a square and tap a symbol on the pad, or type 1 to 9 and the letters A to G on a keyboard.
Levels
There are 256 squares. Easy grids keep at least 150 given symbols and need singles only. Medium keeps at least 125 and needs nothing beyond Medium steps. Hard keeps at least 115 and needs at least one Medium to Expert step. Bigger grids take longer even when the logic is simple, so the clock runs longer than on a 9 by 9 grid at the same level. A puzzle of the day at each level is built from the date, so it is the same grid for everyone who plays that day.
Tips for the big grid
- Scan one symbol at a time through all sixteen boxes. With sixteen symbols it is easy to lose track, and the highlighted copies of the selected symbol help.
- Use pencil marks per box rather than for the whole grid; a box has only sixteen squares.
- Rows and columns with twelve or more symbols placed are quick wins: list the missing four and check each square.
Play features
Hint explains the next step and highlights the squares it uses; Check and Show mistakes mark symbols that do not match the answer; undo and redo keep your full history. Progress and times are saved per level in this browser. For the classic size, play sudoku online; to learn the techniques, read sudoku techniques.
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Questions
Why are there letters in a 16x16 sudoku?
A grid of 16 needs sixteen symbols, and two-digit numbers would not fit in one square. A to G stand for 10 to 16.
Is a 16x16 sudoku harder than a 9x9?
It takes longer, with more squares and symbols to track, but the logic is the same. Our levels are set by the techniques needed, not by size.
Can I type the letters?
Yes. On a keyboard, press 1 to 9 or A to G. On a phone, use the pad under the grid.
Is the daily 16x16 sudoku the same for everyone?
Yes. It is built from the date by our generator, one per level, and changes at midnight on your device.