Free printable kakuro puzzles and tools

Kakuro Solver

Draw the grid, type the clue sums, and press Solve. The solver says whether the puzzle has one solution, several or none.

This free kakuro solver fills in a kakuro puzzle for you. Enter the grid and clues, and it finds the digits that satisfy every sum. It runs in your web browser with no sign-up, and nothing you enter is uploaded or sent to a server.

Use it as a kakuro puzzle solver to check a puzzle from a book or newspaper, to find the mistake in a kakuro grid you designed, or to confirm that your own puzzle has exactly one solution. It works as a kakuro online solver, so there is nothing to install. It accepts grids up to 16 x 16, including the clue row and column.

How to use the kakuro solver

  1. Set Width (columns) and Height (rows) from 4 to 16. Both counts include the clue row and clue column, so row 1 and column 1 are always clue cells.
  2. Click a cell to select it. Click it again, press B, or use the Block cell button to make it black. Press W or use the White cell button to make it white again.
  3. For each selected black cell, type the Down sum (for the run below it) and the Across sum (for the run to its right), from 1 to 45.
  4. Type given digits from 1 to 9 into white cells, using the keyboard or the digit pad. Use the arrow keys to move between cells.
  5. Click Solve. The solution fills in blue, with one of three messages: exactly one solution, at least 2 solutions (one is shown), or no solution.
  6. If a cell is outlined in red, read the message beside the grid. It gives the row and column and the reason, so fix that cell before solving.
  7. To enter a puzzle as text, paste it into the Puzzle text box and click Load text. Copy text exports your grid in the same format.

Load example opens an 8x8 puzzle; Clear empties the grid after a confirmation. Play this puzzle opens your grid in the online player. Print puzzle + solution prints the puzzle page followed by the solution page, on Letter or A4. Copy link stores the grid in the page address as you edit, so you can share it.

What are the rules of kakuro?

A kakuro grid has white cells and black clue cells. You fill every white cell with a digit from 1 to 9. A run is a line of white cells going across or down, and the clue for that run is the sum of its digits. In the usual layout, an across sum sits in the upper right of its clue cell, and a down sum sits in the lower left. No digit may repeat inside a run. Kakuro is also called cross sums.

Short runs are very constrained. A two-cell run with the sum 3 must hold 1 and 2, in either order. A three-cell run with the sum 6 must hold 1, 2 and 3, because that is the only set of three different digits that adds to 6. Each cell belongs to one across run and one down run, so it must satisfy both sums at once.

How does a kakuro solver work?

The solver takes each run and keeps only the digits that appear in at least one set of distinct digits with the right length and sum. It removes digits already used in that run, then combines the across and down possibilities for each cell so that only digits valid in both directions remain. It then searches the choices that are left, one cell at a time, and stops after counting up to two solutions.

This process is what lets the tool tell you whether a puzzle is unique. A grid with a single solution is confirmed when the search finds one fill and no second one. A grid that allows several fills shows one of them and reports that there are at least two.

Why can a kakuro puzzle have more than one solution?

A puzzle has one solution only when its sums leave just one way to fill every run. Long runs with sums near the middle of their range usually allow several combinations of digits. When two runs cross at cells that can swap digits without breaking any sum, the puzzle has more than one valid fill.

Setters usually add a given digit or a black cell to remove the extra fills. When you design your own puzzle, check it with the solver before you publish it, because a grid can look correct and still have two answers.

Frequently asked questions

What if my puzzle has more than one solution?

The solver shows one valid fill in blue and reports “At least 2 solutions. One of them is shown.” Your puzzle is still correct as a grid, but it does not have a single answer. Add a given digit or change a sum to narrow the choices, then solve again.

Can I get a hint instead of the full solution?

Yes. Click Hint to fill one cell that is forced. The tool also says whether it found the digit by sum combinations, by reasoning about a whole run, or by trial and error, and it gives the row and column of that cell.

Why does it say my puzzle is invalid?

Before solving, the tool checks the grid and outlines the problem in red, with its row and column. The usual causes are a run longer than 9 cells, a white cell alone in a run, a run with no sum, a sum that is impossible for its length (for example, a two-cell run with a sum of 2), or a sum that sits next to no run.

Can I paste a puzzle as text?

Yes. Paste the text into the Puzzle text box and click Load text. Rows are separated by /, cells by commas. Use x for a black cell, . for an empty white cell, a digit for a given, and 16\23 for a black cell with down sum 16 and across sum 23. Use - where a side has no sum. For example, x,4\-,6\-/-\3,.,./-\7,.,. is a 3x3 grid with the solution 1 2 / 3 4.