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6x6 Killer Sudoku Puzzles

Six rows, six columns, six boxes of two by three, and the digits 1 to 6: the 6x6 killer sudoku keeps the empty grid and the dotted cages of its big brother, with a third fewer cells to fill. Every row, column and box adds up to 21, and that number does half the work once you get used to it.

Each of these eight puzzles fills a page with a single grid, large enough to pencil small candidates in the corners. They suit anyone who has solved a few 4x4 killer sudoku and wants a longer chain of deductions before moving on to 9x9, and every one of them has a single solution that logic reaches without a guess.

Part of the Sudoku Puzzles collection, Last updated on Tue, 27 Oct 2026 17:43:31 GMT.

Free Printables

6x6 Killer Sudoku, Puzzle 1

6x6 killer sudoku with fourteen cages: a single cell of sum 2, four two-cell cages (3, 4, 7 and 9) and nine three-cell cages, three of them summing to 12 and two to 14. The two-cell cage of sum 3 holds 1 and 2. Puzzle 1 of 8.
6x6 killer sudoku with fourteen cages: a single cell of sum 2, four two-cell cages (3, 4, 7 and 9) and nine three-cell cages, three of them summing to 12 and two to 14. The two-cell cage of sum 3 holds 1 and 2. Puzzle 1 of 8. | zuzuzi.com

6x6 Killer Sudoku, Puzzle 2

6x6 killer sudoku with seventeen cages, four of them single cells (1, 1, 4 and 5) that give four digits at once, seven two-cell cages (3, 6, 6, 7, 8, 9 and 10) and six of three cells, up to a 15 that holds 4, 5 and 6. Puzzle 2 of 8.
6x6 killer sudoku with seventeen cages, four of them single cells (1, 1, 4 and 5) that give four digits at once, seven two-cell cages (3, 6, 6, 7, 8, 9 and 10) and six of three cells, up to a 15 that holds 4, 5 and 6. Puzzle 2 of 8. | zuzuzi.com

6x6 Killer Sudoku, Puzzle 3

6x6 killer sudoku with fourteen cages and no single cell: six two-cell cages (5, 6, 7, 7, 9 and 10) and eight three-cell cages, from a 6 that holds 1, 2 and 3 to a 14. Puzzle 3 of 8.
6x6 killer sudoku with fourteen cages and no single cell: six two-cell cages (5, 6, 7, 7, 9 and 10) and eight three-cell cages, from a 6 that holds 1, 2 and 3 to a 14. Puzzle 3 of 8. | zuzuzi.com

6x6 Killer Sudoku, Puzzle 4

6x6 killer sudoku with fourteen cages: seven two-cell cages (3, 4, 5, 6, 6, 8 and 10), six three-cell cages (8, 8, 13, 13, 15 and 15) and one four-cell cage of sum 12. Each cage of sum 15 can only hold 4, 5 and 6. Puzzle 4 of 8.
6x6 killer sudoku with fourteen cages: seven two-cell cages (3, 4, 5, 6, 6, 8 and 10), six three-cell cages (8, 8, 13, 13, 15 and 15) and one four-cell cage of sum 12. Each cage of sum 15 can only hold 4, 5 and 6. Puzzle 4 of 8. | zuzuzi.com

6x6 Killer Sudoku, Puzzle 5

6x6 killer sudoku with thirteen cages: a single cell of sum 2, five two-cell cages (4, 4, 6, 8 and 10), three of three cells (12, 13 and 15) and four of four cells (12, 12, 13 and 15). The large cages make it one of the harder grids of the set. Puzzle 5 of 8.
6x6 killer sudoku with thirteen cages: a single cell of sum 2, five two-cell cages (4, 4, 6, 8 and 10), three of three cells (12, 13 and 15) and four of four cells (12, 12, 13 and 15). The large cages make it one of the harder grids of the set. Puzzle 5 of 8. | zuzuzi.com

6x6 Killer Sudoku, Puzzle 6

6x6 killer sudoku with thirteen cages: a single cell of sum 2, three two-cell cages (5, 9 and 11, the last one holding 5 and 6), seven three-cell cages from 8 to 14, and two four-cell cages, 10 (which is 1, 2, 3 and 4) and 11. Puzzle 6 of 8.
6x6 killer sudoku with thirteen cages: a single cell of sum 2, three two-cell cages (5, 9 and 11, the last one holding 5 and 6), seven three-cell cages from 8 to 14, and two four-cell cages, 10 (which is 1, 2, 3 and 4) and 11. Puzzle 6 of 8. | zuzuzi.com

6x6 Killer Sudoku, Puzzle 7

6x6 killer sudoku with fifteen cages: two single cells (1 and 4), six two-cell cages (4, 5, 7, 8, 10 and 11), six three-cell cages, three of them summing to 9 and two to 15, and one four-cell cage of sum 13. Puzzle 7 of 8.
6x6 killer sudoku with fifteen cages: two single cells (1 and 4), six two-cell cages (4, 5, 7, 8, 10 and 11), six three-cell cages, three of them summing to 9 and two to 15, and one four-cell cage of sum 13. Puzzle 7 of 8. | zuzuzi.com

6x6 Killer Sudoku, Puzzle 8

6x6 killer sudoku with fourteen cages: two single cells (3 and 5), five two-cell cages (6, 6, 7, 7 and 9), four three-cell cages (6, 10, 10 and 12) and three four-cell cages (13, 14 and 18, the last one holding 3, 4, 5 and 6). Puzzle 8 of 8.
6x6 killer sudoku with fourteen cages: two single cells (3 and 5), five two-cell cages (6, 6, 7, 7 and 9), four three-cell cages (6, 10, 10 and 12) and three four-cell cages (13, 14 and 18, the last one holding 3, 4, 5 and 6). Puzzle 8 of 8. | zuzuzi.com

How to Solve a 6x6 Killer Sudoku

Start with the cages that allow only one set of digits: a two-cell cage of sum 3 holds 1 and 2, one of sum 11 holds 5 and 6; a three-cell cage of sum 6 is 1, 2 and 3, and one of sum 15 is 4, 5 and 6. Then use the rule of 21: a row, a column or a 2x3 box adds up to 21, so when cages fill a box except for one cell, that cell is 21 minus their sums. The cages that straddle the thick line between two boxes are the key moments: compare what each side must hold.

Write candidates small, cross them off as digits land, and come back to the cage that has just lost all but one option. Nothing in these grids needs a guess.

Frequently Asked Questions

How is a 6x6 killer sudoku different from a 9x9?

The grid uses the digits 1 to 6 and boxes of two rows by three columns instead of three by three. The cages work the same way, but the sums are smaller, the chains of deductions shorter, and a puzzle takes a fraction of the time of a 9x9.

What do a row, a column and a box add up to?

To 21, the sum of 1 to 6. It is the most useful number of the grid: whenever cages fill a row or a box except for one or two cells, the missing cells must make up the difference to 21.