25×25 Sudoku Rules: How Giant Sudoku Works
Learn the rules of 25x25 Sudoku, how 5x5 boxes work, and where to use the Pure Sudoku 25x25 grid.
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Get the iPhone App →25×25 Sudoku is a giant Sudoku variant with 25 rows, 25 columns, and twenty-five 5×5 boxes. If you want the hands-on version, open the Pure Sudoku 25×25 Sudoku grid first, then use this guide to understand the rules.
The core 25×25 Sudoku rule
The rule is the same as classic Sudoku: every row, every column, and every box must contain each symbol exactly once. In a 25×25 puzzle, the symbols are usually 1 through 25, although some publishers use letters or mixed symbols.
- 25 rows
- 25 columns
- 25 boxes, each box measuring 5 cells by 5 cells
- 625 total cells
- 25 unique symbols per row, column, and box
Why 25×25 feels different from normal Sudoku
The logic is familiar, but the scale changes the experience. A classic 9×9 puzzle has 81 cells. A 16×16 Hexadoku has 256 cells. A 25×25 grid has 625 cells, so visual organization matters as much as solving technique.
A clean way to start
Start by scanning one 5×5 box at a time. Then compare that box against the matching five rows and five columns. Avoid trying to track all 25 symbols mentally; use candidates or printed notes when the grid becomes crowded.
For a smaller large-grid stepping stone, try Hexadoku online. For the full giant grid, use the 25×25 Sudoku page.
FAQ
Is 25×25 Sudoku real Sudoku? Yes. It follows the same row, column, and box uniqueness rule as standard Sudoku.
How big are the boxes? Each box is 5×5, giving 25 boxes across the full grid.