Home › Fun & Games › Kakuro Puzzle
Kakuro Puzzle
Kakuro is a crossword made of numbers: fill the white cells with 1–9 so each run adds up to the clue on its left or above, without repeating a digit. Choose a grid size, use pencil marks and let the combination helper show which digits can make each sum.
Last updated:
⏱ 00:00
Combination helper
Select a white cell to see the combinations for its across and down sums.
Combination finder
Advertisement
Advertisement
How to use the Kakuro Puzzle
- Pick a grid size. 6×6 is a gentle start; 12×12 is a long expert puzzle.
- Select a white cell and enter a digit with the number pad or keyboard. Each clue cell shows the total of the run to its right (top number) and the run below it (bottom number).
- Use the combination helper: it lists every set of different digits that can make the selected runs, and the digits that fit both.
- Take notes with Notes mode or Shift+digit, and use Undo freely.
- Finish the grid so every run adds up to its clue with no repeated digits. Use Check to find mistakes or Reveal cell if you're stuck.
Kakuro combinations with only one answer
Memorising these "magic" totals is the quickest way to get better at kakuro. The digits can appear in any order within the run.
| Cells | Lowest unique total | Second lowest | Second highest | Highest unique total |
|---|---|---|---|---|
| 2 | 3 = 1+2 | 4 = 1+3 | 16 = 7+9 | 17 = 8+9 |
| 3 | 6 = 1+2+3 | 7 = 1+2+4 | 23 = 6+8+9 | 24 = 7+8+9 |
| 4 | 10 = 1+2+3+4 | 11 = 1+2+3+5 | 29 = 5+7+8+9 | 30 = 6+7+8+9 |
| 5 | 15 = 1+2+3+4+5 | 16 = 1+2+3+4+6 | 34 = 4+6+7+8+9 | 35 = 5+6+7+8+9 |
| 6 | 21 = 1–6 | 22 = 1+2+3+4+5+7 | 38 = 3+5+6+7+8+9 | 39 = 4–9 |
| 7 | 28 = 1–7 | 29 = 1–6 + 8 | 41 = 2+4+5+6+7+8+9 | 42 = 3–9 |
| 8 | Any total from 36 to 44: the missing digit is 45 − total | |||
| 9 | Always 45 (1 to 9) | |||
Solving tips
- Use the crossings. A cell belongs to an across run and a down run, so its digit must appear in the possible combinations of both. If one run needs 7+9 and the other 1+2+4, nothing fits; if it is 1+3 and 1+2+4, the cell must be 1.
- Look for big and small extremes. A 2-cell run of 16 and a crossing run that can't contain 9 forces the 7.
- Subtract filled digits. Once some cells in a run are filled, the rest must make up the remaining total with digits not used yet. The helper shows this "left" total for you.
- Remember the 8-cell trick. An 8-cell run is just 1 to 9 with one digit missing, and that digit is 45 minus the clue.
Frequently asked questions
What are the rules of kakuro?
Fill every white cell with a digit from 1 to 9. Each horizontal run of white cells must add up to the number in the clue cell on its left, and each vertical run must add up to the number in the clue cell above it. A digit may not appear twice in the same run.
How do I read the clue cells?
Clue cells are split by a diagonal line. The number in the top-right half is the sum of the run going right (across); the number in the bottom-left half is the sum of the run going down.
Which kakuro sums have only one combination?
In two cells, 3 is always 1+2, 4 is 1+3, 16 is 7+9 and 17 is 8+9. In three cells, 6 = 1+2+3, 7 = 1+2+4, 23 = 6+8+9 and 24 = 7+8+9. In four cells, 10 = 1+2+3+4, 11 = 1+2+3+5, 29 = 5+7+8+9 and 30 = 6+7+8+9. These are the best places to start.
Does each puzzle have a unique solution?
Yes. Every puzzle was generated and then verified by a solver that proved only one way to fill the grid exists, so it can always be solved by logic without guessing.
What is the best strategy for kakuro?
Start with runs that have only one combination, then look at cells where an across run and a down run cross: the digit must be in both runs' possible sets. Use the fact that digits can't repeat in a run, and fill in pencil marks so you can eliminate candidates.
Is kakuro the same as cross sums?
Yes. Kakuro is the Japanese name popularised by the puzzle publisher Nikoli; the puzzle was first published in the United States as Cross Sums. Both names describe the same rules.
Can I play with a keyboard?
Yes. Arrow keys move between white cells, 1–9 enter a digit, Shift+1–9 adds a note, Backspace erases, N toggles notes mode, P pauses and Ctrl+Z undoes.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.
Related tools
Killer SudokuPlay generated killer sudoku puzzles with cage sums, pencil marks, a cage combo helper and hints.Sudoku OnlinePlay free Sudoku with 4 difficulty levels, notes, hints and a timer.Nonogram PuzzlePlay unlimited nonogram (picross) puzzles from 5×5 to 15×15, each with one unique solution.Math Quiz GameTimed mental math rounds with four operations, five levels, streaks and high scores.SolitairePlay classic Klondike Solitaire with Draw 1 or Draw 3 and undo.Spider SolitairePlay Spider Solitaire online with 1, 2 or 4 suits, hints, unlimited undo and a timer.Play Chess vs ComputerPlay chess online against the computer at 8 difficulty levels.Connect FourPlay Connect 4 online against the computer or a friend.Snake GamePlay classic Snake online with speeds, wall modes and high scores.Tic Tac ToePlay tic tac toe against an unbeatable AI or a friend.Block Puzzle GameClassic falling blocks puzzle game with levels and high score.MinesweeperPlay classic Minesweeper: 3 difficulties, flags, timer and a safe first click.2048 GamePlay 2048 online with swipe controls, undo and best score.Word Guess GameGuess the hidden five-letter word in six tries. Unlimited games, stats and hard mode.HangmanClassic friendly hangman word game with categories, hints and difficulty levels.Memory Card GameFlip cards and match emoji pairs on 4×3 to 6×6 grids, with moves, timer and best scores.Flappy GameTap to flap a round chick through bamboo gaps and beat your high score.Dino Runner GameJump cacti and duck buzzing beetles in an original endless desert runner.Typing GameType the falling words before they land; level up and track your WPM and accuracy.Flag QuizGuess the flags of all 196 countries in four modes, from multiple choice to timed.Map QuizFind countries on a clickable world map or name the highlighted one, by continent.Periodic Table QuizLearn all 118 elements: quiz symbols, names and atomic numbers or click them on the table.Spelling Bee GameMake words from 7 honeycomb letters, always using the center letter. New daily puzzle.Jigsaw PuzzleTurn a sample picture or your own photo into a 12 to 150 piece jigsaw puzzle and solve it.Sliding PuzzlePlay the 15 puzzle and 3×3 to 6×6 sliding tile puzzles with numbers or your own photo.Mahjong SolitaireMatch pairs of free tiles to clear the Turtle and two smaller layouts, with hints, shuffle and undo.Scrabble Word FinderFind the highest-scoring words from your rack, with blank tiles, patterns and bingo bonus.Wordle SolverEnter your guesses and colours to see every possible answer and the best next guess.Crossword SolverFind words that fit a crossword pattern like c?t from the length and the letters you know.Word Search GeneratorMake a word search puzzle from your words, play it online or print it with an answer key.Pong GamePlay classic Pong online against the computer on 3 levels or with a friend, first to 11.Breakout GameClassic brick breaker game with levels, power-ups and lives. Play with mouse, touch or keyboard.Whack-a-MoleWhack the moles before they hide in 30 or 60 second rounds. Speed increases, best score saved.Simon Says GameRepeat the growing color and sound sequence. Classic memory game with strict mode and high score.CheckersPlay checkers online against the computer or a friend, with kings, undo and hints.ReversiPlay Reversi (Othello rules) online vs a 3-level computer or a friend, with move hints.GomokuGet five in a row on a 15×15 board against a smart computer or a friend.Battleship GamePlace your fleet and sink the computer's ships in this classic naval guessing game.FreeCellPlay FreeCell solitaire online with the classic numbered deals, undo, hints and auto-move.Mastermind GameCrack the secret 4-color code in 10 tries using black and white feedback pegs.Tower of HanoiPlay the Tower of Hanoi puzzle with 3 to 8 disks, or watch it solve itself in the fewest moves.Maze GeneratorCreate random mazes in any size, solve them with the arrow keys, then print or save as PNG.Sudoku SolverType in any Sudoku and solve it instantly, get step-by-step hints and check it has one solution.Bingo Card GeneratorMake printable 75-ball or custom word bingo cards, from 1 to 200 unique cards, as PDF or print.Bingo Number GeneratorFree bingo caller for 75 or 90 balls with a live board, auto-call timer and spoken numbers.Online ScoreboardKeep score for any game: big team scores, game clock, periods, fullscreen and sport presets.Trivia Quiz300+ general knowledge trivia questions in 10 categories. 10-question rounds with a timer and score.Random Riddle Generator150+ riddles with hidden answers in easy, hard and kids levels. Guess, get a hint or reveal.Crossword Puzzle MakerTurn a list of words and clues into a crossword you can play online, share or print.Pyramid SolitairePlay Pyramid Solitaire online: pair cards that add up to 13 and clear the pyramid.Yacht Dice GamePlay the classic 5-dice scoring game solo for a high score or against a friend.MancalaPlay Mancala (Kalah rules) online against a smart computer or a friend on one screen.Lights Out GameTurn off every light in the classic 5x5 puzzle, with solvable random boards and a solver.BackgammonPlay backgammon online vs the computer or a friend, with doubling cube, undo and match scoring.Bubble Shooter GameAim, bounce and match 3 or more colored bubbles to pop them before the ceiling comes down.World Capitals QuizGuess the capital city of every country, by region, with multiple choice or typed answers.Categories Game GeneratorRandom letter and 12 categories from a 700+ pool, with round timer, printable sheets and scores.Chinese CheckersPlay Chinese checkers on a star board for 2, 3, 4 or 6 players, against friends or the computer.3x3 Cube SolverPaint your scrambled 3x3 cube and get a short step-by-step solution with a 3D animation.Dominoes GamePlay draw or block dominoes with a double-six set against 1 to 3 computer players.Emoji QuizGuess the word, phrase, animal, food or movie from emoji clues. 370+ puzzles with hints.Funny Fill-in-the-Blank Story GeneratorWord game: fill in nouns, verbs and adjectives without seeing the story, then reveal it.Golf SolitairePlay Golf Solitaire online: clear 7 columns by playing cards one rank up or down. 9-hole scoring.Guess the Number GameGuess the secret number with higher/lower or warm/cold hints, or let the computer guess yours.Hearts Card GamePlay Hearts online against 3 computer players: pass cards, dodge the Queen of Spades, shoot the moon.Ludo GamePlay Ludo online with 2-4 players or against the computer: roll, capture and race home.Match 3 GameSwap gems to match 3 or more, trigger cascades and special gems, and beat each level's target.Snakes and LaddersPlay the classic board game online with 2-4 players or against the computer.