Medium 6x6 Sudoku

A 6×6 grid using digits 1–6. Each row, column, and 2×3 box must contain every digit once. The perfect step between 4×4 and 9×9. Free online.

Easy Medium Hard

Medium 6x6 Sudoku with about 18 givens. You will need to cross-reference rows, columns, and 2×3 boxes at the same time to find each placement.

4
1
1
3
5
5
4
2
3
1
5
6
1
4
3
4
1
5
Mistakes
0/3
Score
-
Time
00:00
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Progress0%

How to Play Medium 6x6 Sudoku

Fill the grid so that every row, every column, and every 2×3 box contains the digits 1 through 6 exactly once. The boxes are rectangles — two rows tall and three columns wide — marked by the thicker lines after row 2, row 4, and column 3. Start with the rows, columns, and boxes that already hold the most digits: where only one digit is missing, it places itself. That technique, the obvious single, carries you through most 6×6 puzzles.

If 6×6 still feels like a stretch, warm up on 4×4 Mini Sudoku first — it teaches the same rule on a smaller board and is the format we recommend on our Sudoku for Kids page. And when hard 6×6 stops slowing you down, take the leap to a full easy 9×9 Sudoku — the logic is identical, just bigger.

Frequently Asked Questions — Medium 6x6 Sudoku

What makes medium 6x6 Sudoku harder than easy?
Medium puzzles start with around 18 givens instead of 22. Fewer filled cells mean single scans rarely solve a cell on their own — you must cross-reference a row, a column, and a 2×3 box at the same time to pin a digit down.
Do I need pencil marks for medium 6x6 Sudoku?
They help but are rarely essential. With only six candidates per cell, most players can hold two or three possibilities in their head. If a cell stubbornly resists, note its candidates and watch for one to be eliminated by a placement elsewhere.
Which techniques solve medium 6x6 puzzles?
Obvious singles plus simple candidate elimination cover nearly everything. Occasionally a pair of cells in one box will share the same two candidates, which excludes those digits from the rest of the box — the same naked-pair logic used on 9×9 grids, in miniature.
How long does a medium 6x6 Sudoku take?
Expect four to six minutes. It is the sweet spot of the format: enough deduction to feel satisfying, short enough to finish in one sitting.

More questions? See the full 6x6 Sudoku guide.