Sudoku-YFoundations
Sudoku Sizes Compared: 4×4, 6×6, 9×9 & 16×16
Standard Sudoku is 9×9, but you can start smaller or go bigger. Compare the four layouts below, check which numbers and box shapes each uses, then jump into a game. The no-repeat rule stays the same.
Same idea. Different-sized boxes.
The green area is one box. Every row, column and box needs the full set once. These empty grids show the layout, not puzzles to solve.
4×4
Use 1–4 · 16 cells
2 rows × 2 columns per box
A small board to get started.
Try 4×4 →6×6
Use 1–6 · 36 cells
2 rows × 3 columns per box
Watch the rectangular boxes.
Try 6×6 →9×9
Use 1–9 · 81 cells
3 rows × 3 columns per box
The classic, with our full technique tools.
Try 9×9 →16×16
Use 1–16 · 256 cells
4 rows × 4 columns per box
More cells to scan; not always harder logic.
Try 16×16 →These are Sudoku-Y’s layouts. Other sites may rotate 6×6 boxes or use letters on 16×16. Check the thick borders and symbol set before you start.
Read the box shape
A 4×4 grid uses 2×2 boxes; 9×9 uses 3×3 boxes; 16×16 uses 4×4 boxes. A 6×6 grid uses rectangular six-cell boxes, not 3×3 boxes. Follow the thick boundaries.
The sets used by Sudoku-Y
- 4×4: values 1–4, 16 cells, boxes 2 rows high and 2 columns wide.
- 6×6: values 1–6, 36 cells, boxes 2 rows high and 3 columns wide.
- 9×9: values 1–9, 81 cells, boxes 3 rows high and 3 columns wide.
- 16×16: values 1–16, 256 cells, boxes 4 rows high and 4 columns wide.
These are Sudoku-Y conventions. Other sites may use different symbols or box orientations. Classic treats values as symbols; Killer also uses their numerical sums.
Transfer the same reasoning
Original example: in a 6×6 grid, a blank cell sees {1,4} in its row, {2,6} in its column and {3} in its box. Combining the forbidden values leaves only 5. This is the same single-candidate reasoning used in 9×9, starting from 1–6 instead.
Complete candidate notes before searching for pairs or subsets. Count a forbidden digit only once even if both the row and column exclude it.
Try before revealing
A 4×4 row reads 1, blank, 4, 2. Should you consider 5, and what belongs in the blank?
Show explanation
Do not consider 5: the set is 1–4. The row needs 3. If its column or box already contains 3, the board state is inconsistent and needs checking; a value outside the set cannot fix it.
Which Sudoku size should I try first?
- New to Sudoku? Try 4×4 to get used to checking a row, a column and a box. You only need four symbols.
- Want a step up? Try 6×6. Its rectangular boxes are a good reminder to follow the thick lines.
- Want the familiar game? Start with easy Classic 9×9. This is also the size supported by our full technique scanner.
- Enjoy keeping track of lots of candidates? Try 16×16. Sudoku-Y uses numbers 1–16, so there is no letter key to learn here.
Bigger does not automatically mean harder logic. The starting clues and the deductions needed matter too. If you are learning the rules, choose a board you can read comfortably before adding more cells.
Want to practise before playing? Try a Single with a worked explanation, or walk through the basic rules.
References and further reading
Read the source explanations and compare them with our examples. Links are references, not endorsements or claims of affiliation.