Sudoku 12×12 Solver
Enter digits 1–9 and letters A–C (for 10–12). Every row, column, and 3×4 box must contain each of the 12 symbols exactly once.
or generate a puzzle to get started
About 12×12 Sudoku
The 12×12 Sudoku uses a 144-cell grid divided into twelve 3×4 rectangular boxes. Instead of the usual 1–9, you use digits 1–9 and letters A, B, C (representing 10, 11, 12).
This variant bridges the gap between the 9×9 Classic and the 16×16 Super Sudoku, offering a satisfying challenge for experienced puzzlers.
Frequently Asked Questions
What symbols are used in 12×12 Sudoku?
Digits 1–9 plus the letters A (10), B (11), C (12).
What shape are the boxes?
3 rows × 4 columns — rectangular, not square like in the 9×9.
Is it harder than 9×9?
Yes. More cells and symbols make it harder, though the same logical techniques still apply.
How to Play Sudoku 12×12
1 Rules
- ✓ Fill every row with all 12 symbols (digits 1–9 and letters A–C), no repeats.
- ✓ Fill every column with all 12 symbols, no repeats.
- ✓ Fill every 3×4 rectangular box with all 12 symbols, no repeats.
- ✓ Pre-filled clue cells cannot be changed.
2 Strategies
- 💡 Letter–Number Separation: Scan for digits 1–9 and letters A–C in separate passes. Beginners often miss letter placements when scanning for numbers only.
- 💡 3×4 Box Row Logic: Boxes span 3 rows × 4 columns — if a symbol already appears in two of the three rows within a box, it must fill a cell in the third row of that box.
- 💡 Naked Pairs: With 12 symbols per unit, naked pairs and triples appear frequently. Identifying them early cuts the candidate lists in half and accelerates the entire solve.
Tip: Keep a mental note that A=10, B=11, C=12. Mixing up letters and their numeric values is the most common source of errors in 12×12 puzzles.