A 16×16 sudoku (giant or hexadecimal sudoku) uses sixteen symbols instead of nine: every row, column and 4×4 box must hold each of them once. This 16x16 sudoku solver uses the symbols 1 to 9 and A to G, where A stands for 10 and G for 16, and finds the solution of a 256-cell grid in your browser.
How to enter the grid
- Tap a cell and type 1 to 9 or A to G on the keyboard, or use the 16-key pad under the grid.
- If your puzzle uses 0 to F instead, add one to each symbol: 0 becomes 1, 9 becomes A, F becomes G.
- To paste, use 256 characters (dots for blanks), or 256 numbers from 1 to 16 separated by spaces or commas, with 0 for blanks.
- Press Solve, or Next hint for one step at a time.
How it is solved
Giant sudoku has the same logic as the classic puzzle on a bigger scale, so all the techniques carry over: hidden singles in a box, row or column; naked and hidden pairs, triples and quads; pointing and box/line reductions; fish and wings. The exact search proves the solution is unique before the hints start, so a hint never leads you into a dead end. With 256 cells there are many more steps; the step list shows them all, and you can click any step to see the grid at that moment.
Hidden singles carry most of the work in 16×16 puzzles because each unit has sixteen cells to rule out. Turn on Show all candidates when you get stuck: the small 4×4 marks in each cell show which symbols are still possible.
Tips
- Scan one symbol at a time across the sixteen boxes; it is the fastest way to find hidden singles by eye.
- On a phone, turn the screen sideways for bigger cells.
For five overlapping 9x9 grids instead of one large one, use the samurai sudoku solver. The classic 9x9 has the sudoku solver, with a hint for every step.
Prefer to play? 16x16 sudoku online has easy, medium and hard grids with pencil marks and hints.
Solver tested . Found a problem? Tell us.
Questions
What symbols does a 16x16 sudoku use?
Usually 1 to 9 and A to G, or 0 to 9 and A to F, or the numbers 1 to 16. This solver shows 1 to 9 and A to G and accepts 1 to 16 when you paste numbers.
How big are the boxes in a 16x16 sudoku?
4 by 4, so each box holds sixteen cells, the same as a row or a column.
How long does the solver take for a 16x16 grid?
A well-formed puzzle is usually solved in well under a second on a phone or laptop. A grid with very few clues can take longer; the search runs in the background with a Cancel button.
Can I solve 12x12 or 25x25 sudoku here?
Not yet. The site has solvers for 9×9, 6×6 and 4×4 and for 16×16.