What is it?
Kakuro is a crossword made of numbers. Each grey square holds clues: the number in its top-right corner is the total of the white squares to its right, and the number at the bottom-left is the total of the squares below it. Fill every white square with 1 to 9 so that all runs add up, without repeating a digit in the same run.
Who is it for?
Sudoku players who want a new challenge, students practising mental addition, and puzzle fans who like logic with numbers.
How to use it
- Pick a Size: Small (5 × 5), Medium (7 × 7) or Large (9 × 9), and press New puzzle.
- Tap a white square, then a number on the pad (or type 1–9; arrows move).
- The line under the board shows the current run’s total and what is still needed.
- Tap the same square again, or press Space, to switch between the across and down run.
- When everything adds up you see Every run adds up and no number repeats. Use Reveal square (+10 seconds), Clear or Show answer if needed.
Starting tricks
- Some totals can be made only one way: two squares adding to 3 must be 1 and 2; two adding to 17 must be 8 and 9; three adding to 6 must be 1, 2 and 3; three adding to 24 must be 7, 8 and 9.
- Start where two such runs cross: the shared square must be a digit both allow.
- Small 5 × 5 puzzles take a few minutes and are the best place to learn.
Errors and how to fix them
- A number turns red: it repeats a digit in its run, or makes the run’s total too big (or wrong once the run is full).
- “Making a puzzle…” stays for a moment: larger grids take a little longer to build on older phones.
- My answer differs from Show answer but was accepted: any grid where every run adds up with no repeats counts.
- The board is too small or cut off on my phone: turn the phone sideways, or zoom out the page; the board fits the width of the screen.
- My game, best time or score has gone: it is kept only in this browser on this device. Private windows, clearing site data, or another browser or phone start fresh.
Open the tool: Kakuro
Still stuck?
Contact support. Tell us which tool or page you were using, what you tapped, what you saw, and your phone or computer and browser (for example: Android phone, Chrome). We reply by email.
Questions, or an error not listed here?
Tell us in the comments: what you were doing, the exact message you saw, and your device and browser. We read every comment and add new fixes to this article.