What is 16×16 Sudoku?
16×16 Sudoku is a larger version of classic sudoku, also known as Mega Sudoku. It has 16 rows, 16 columns and 256 cells. On this page, you fill the empty cells with numbers from 1 to 16.
The board is split into sixteen boxes, each one 4 cells tall and 4 cells wide. Each row, each column and each of those sixteen 4×4 boxes must contain every number from 1 to 16 with no repeats. If you have already played our classic 9×9 sudoku or our 12×12 Sudoku, the row, column and box rules will feel familiar. The extra cells give you more places to practise them.
You do not need to tackle all 256 cells at once. Work through one row, column or box, then check how each new number helps the cells around it.
How is 16×16 different from a normal sudoku?
Classic 9×9 sudoku uses numbers 1–9 in 3×3 boxes. Here, the number set grows to 1–16 and each box grows to 4×4. Numbers 10 to 16 each fill one cell, just like the smaller numbers.
That is the only real difference. There are no extra rules and no hidden tricks. If you can read a row, a column and a 4×4 box, you can play 16×16 Sudoku.
- 🟪 Every row needs the numbers 1–16 with no repeats
- 🟦 Every column needs the numbers 1–16 with no repeats
- 🟧 Every 4×4 box needs the numbers 1–16 with no repeats
- 🔢 The pad shows all sixteen number buttons in two tidy rows of eight
The 3 simple rules
-
One of each in every row
Every one of the sixteen rows must contain the numbers 1 through 16 — no repeats.
-
One of each in every column
Every one of the sixteen columns must contain the numbers 1 through 16 — no repeats.
-
One of each in every 4×4 box
Each of the sixteen boxes (four cells tall, four cells wide) must contain the numbers 1 through 16 — no repeats.
How to start a 16×16 Sudoku
Start on Easy and find a row, column or box with only a few gaps. List the numbers it is missing, then check each empty cell against its crossing row, column and box.
For example, if a row is missing 6 and 14, look down the columns of its two empty cells. If one column already contains 14, that cell must be 6. The other empty cell in the row must be 14.
You can also scan for one number at a time. In a box that needs a 12, rule out empty cells whose rows or columns already contain 12. If only one place remains, you have found the next move.
Easy strategies for kids
- ✨ Start in the box with the most starter numbers
- 📐 Scan one number at a time — find every place a 1 could go, then 2, then 3…
- 🔢 Check which number is missing when a row, column or box has one gap
- ✏️ Tap Notes to pencil in the small "maybe" numbers
- 💡 Auto Notes fills the candidate numbers in for you on every empty cell
- 🧠 Take breaks — a fresh look spots clues your tired eyes missed
Brand new to sudoku? Do a few rounds of 4×4 sudoku first, then 6×6 sudoku, then graduate to classic 9×9 sudoku, then 12×12 Sudoku. Once 12×12 Easy feels routine, 16×16 Sudoku is the perfect next step up.
Make the bigger board manageable
- 🧠 Focus on one row, column or box at a time
- ✏️ Use notes to keep track of numbers you are still considering
- 🕵️ Recheck nearby cells after each placement
- ⏱️ Take breaks whenever you want — there is no time limit
- 📱 Try a tablet or laptop if you would like more room to see the grid
Ready for more?
Once Easy 16×16 Sudoku feels comfortable, try Medium 16×16 Sudoku. From there you can graduate to Hard 16×16 Sudoku, and finally take on Expert 16×16 Sudoku — the highest difficulty in our 16×16 collection.
Want a totally different brain workout? Try our X-Sudoku (sudoku with two big diagonals), our Killer Sudoku (sudoku with cage sums) or our Jigsaw Sudoku (classic rules, but the boxes are wiggly shapes).
Frequently asked questions
Is 16×16 Sudoku suitable for kids?
It is a good next puzzle for children who are comfortable with classic 9×9 sudoku and want a larger board. Start with Easy and use notes or hints as needed. New players can build confidence with 4×4 or 6×6 first.
Is 16×16 Sudoku harder than 9×9?
The board has more cells and more numbers to track, so it can take longer to work through. Difficulty also depends on the starting clues. The same row, column and box techniques work on both sizes.
Why are the boxes 4×4?
A 4×4 box has sixteen cells, enough for each number from 1 to 16 to appear once. The full board contains sixteen of these boxes.
Does 16×16 Sudoku use numbers or letters?
This game uses numbers 1–16. Some 16×16 puzzles use a mix of numbers and letters to represent sixteen different symbols. Either way, each symbol must appear once per row, column and 4×4 box.
How long does an Easy 16×16 take?
The time depends on your experience and how often you use notes or hints. Give yourself time to explore the larger board and take breaks whenever you like. There is no time limit.
Can I play without making an account?
Yes! Every game on this site is free, with no signup, no email, and no ads in the way of the puzzle.
Does it save my progress?
Yes — your puzzle, notes and timer save automatically in your browser when browser storage is available. Return in the same browser to continue. Clearing site data removes the saved game.
Try other sudoku games
Different rules, same friendly board. Pick a sibling puzzle to play next.