All Sudoku Variants
25×25 · Size Variant

Sudoku 25×25

Also known as Giant Sudoku

A 25×25 grid with 5×5 boxes using 25 symbols — one of the largest square formats in common use.

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An example 25×25 Sudoku: twenty-five symbols fill every row, column and 5×5 box (a few 1–9 shown).

25×25 Sudoku is one of the largest formats in common use: a twenty-five-by-twenty-five grid divided into 5×5 boxes, filled with twenty-five different symbols — usually the numbers 1–25 or the letters A–Y. Each row, column and box must hold all twenty-five once. It is a marathon, and it rewards patience far more than cleverness.

The rule: twenty-five symbols per row, column and 5×5 box

Fill the grid so every row, every column and every 5×5 box contains all twenty-five symbols exactly once. A single 5×5 box already holds a complete set — below, one box is filled with 1 through 25 to show the range.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

One 5×5 box holds all twenty-five symbols (1–25). The full grid has twenty-five such boxes.

Patience over difficulty

A 25×25 is not harder in principle than a 9×9 — the techniques are the same — but the scale is enormous: 625 cells, twenty-five candidates each, and boxes five wide. Careful, complete pencil-marking is not optional; a single missed elimination is very easy to make and painfully slow to find. Approach it as a long, calm project, working steadily one unit at a time.

Numbers or letters

Puzzles for a general audience use 1–25, which is unambiguous but makes most cells two characters wide. Others use the letters A–Y, keeping every cell a single character. The logic is identical either way — the symbols are just labels for twenty-five distinct values.

Solving strategy

  • Pencil-mark everything. With twenty-five possibilities per cell, thorough notes are the only way to stay on track.
  • Work box by box. Finish one 5×5 box before moving on, to avoid losing your place.
  • Hunt hidden singles per symbol. Take one symbol at a time and place it wherever it is confined to a single cell.
  • Use the same techniques as 9×9. Naked pairs, hidden singles and X-Wings all scale up unchanged.

Common mistakes

  • Sloppy candidate marks. On a grid this vast, one wrong mark can waste hours.
  • Forgetting a symbol. All twenty-five must appear — it is easy to overlook one when scanning.
  • Mixing labelling schemes. Decide whether the grid uses 1–25 or A–Y and stick with it.
  • Rushing. The 25×25 is a test of stamina and care, not speed.

Can I play it here?

Not yet — Sudoku 25×25 isn't one of the puzzle types SudokuStreak generates for now. But you can learn its rules above, and there's plenty here to sink your teeth into meanwhile: