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How to Print Classic Sudoku on A4 Paper
A4 measures 210 × 297 mm and is the international ISO standard used across Europe, the UK, Asia, and Australia. Print 6 puzzles per page comfortably on A4. Set the paper size to A4 in the generator, print at 100% scale rather than Fit to page, and the cells come out at the size they were designed for. Every puzzle has a guaranteed unique solution.
Why A4
Why Print Classic Sudoku on A4?
A4 is the international ISO standard used across Europe, the UK, Asia, and Australia — choose this size when printing on local stationery, or to fit standard binders and folders. Dimensions: 210 × 297 mm.
Print 6 puzzles per page comfortably on A4.
About this puzzle
About Classic Sudoku
Classic Sudoku uses a standard 9×9 grid divided into nine 3×3 regions. Each puzzle has a single unique solution reachable through logical deduction without guessing. The classic format spans all difficulty levels.
Grid: 9×9. Clue count: 30–35.
Read the full classic sudoku guide or open the live generator.
How to solve
How to Solve Classic Sudoku — Quick Walkthrough
Classic solving combines all techniques depending on difficulty calibration. Begin with row-by-row scanning for naked singles. Move to column-by-column. Finish with box-by-box. If unresolved cells remain, escalate to hidden singles, then candidate notation if needed.
Pro tips
Tips for Classic Sudoku Solvers
- Treat Classic Sudoku as a difficulty calibration rather than a unique format. Adjust your strategy based on the clue count: 36+ clues use Easy techniques, 30–35 use Medium, below 30 use Hard.
- Newspaper Classic puzzles typically sit at Medium difficulty. Use hidden singles and naked pairs as your primary techniques.
- Practice mental scanning on Classic Sudoku. The 9×9 format is ideal for building pattern recognition that transfers to all Sudoku variants.
- Solve Classic Sudoku on paper at least once a week. The physical act of scanning a printed grid builds spatial reasoning that on-screen solving cannot replicate.
Different size?
Other Paper Sizes
Other difficulties
A4 in Other Difficulties
Want a different difficulty on A4 paper? Easy Sudoku — A4 · Medium Sudoku — A4 · Hard Sudoku — A4 · Expert Sudoku — A4 · Mini Sudoku — A4 · Kids Sudoku — A4 · Large Print Sudoku — A4.
FAQ
Classic Sudoku — A4 — Common Questions
What makes a Sudoku puzzle 'classic'?
Classic Sudoku refers to the standard 9×9 grid divided into nine 3×3 regions, the format invented by Howard Garns in 1979 and popularised by Japanese puzzle magazines from the 1980s. Classic Sudoku is format-defining rather than difficulty-defining.
Can Classic Sudoku be any difficulty?
Yes. The Classic format is independent of difficulty — Classic puzzles can be Easy, Medium, Hard, or Expert depending on clue count and distribution. When solvers say 'Classic Sudoku' they usually mean the standard format at Medium difficulty.
How is Classic Sudoku different from variant Sudokus?
Variant Sudokus add extra constraints (diagonal sums, killer cages, X-Sudoku, hyper-Sudoku regions) on top of the standard rules. Classic Sudoku has only the three core constraints: each digit 1–9 must appear exactly once in each row, column, and 3×3 box.