Calcudoku Game
Use each number once per row and column. Make every cage target.
Daily puzzle · UTC
Keyboard help & personal bests
Arrows move. Enter digits allowed by the grid size. N toggles notes. Backspace, Delete or 0 erases. Enter checks.
Progress and personal bests are saved in this browser.
How to Play Calcudoku
Calcudoku combines a number grid with arithmetic cages. A 4×4 grid uses 1 through 4, a 5×5 grid uses 1 through 5, and a 6×6 grid uses 1 through 6. Fill every cell so each number appears exactly once in each row and column. There are no additional Sudoku-style box rules.
Each cage has a thick outline and a target in its upper-left cell. Combine the numbers inside that cage using the shown operation to reach the target. Addition and multiplication cages can contain several cells. Subtraction and division cages contain exactly two cells: use their positive difference or larger-number-to-smaller-number quotient.
A cage with one cell displays only its target; that number is filled as a fixed clue. A digit may repeat inside a larger cage when its cells are in different rows and columns. Select a cell to see its cage target in the text below the board. Each generated puzzle is checked to have one solution using only its displayed cages and row/column rules.
Work Through Cage Examples
A two-cell cage labeled 7+ on a 4×4 board must contain 3 and 4 in some order. For a 3− cage, the two values are 1 and 4. A 2÷ cage could contain 1 and 2 or 2 and 4; their row and column positions help decide which pair fits. The order of entry does not change the subtraction or division rule.
A three-cell cage labeled 6× has values whose product is six, such as 1, 2 and 3. Before entering an answer, check whether a proposed digit already appears in that cell’s row or column. Cage arithmetic alone is not enough: every row and column must also have the full set of digits once.
Use Notes to keep candidates. Press a candidate again to remove it, and switch Notes off before entering a final value. Repeated row or column numbers and incorrect completed cages are marked. Check reviews entered values. Hint supplies one correct value and marks the result as assisted.
Levels, Keyboard Controls and Progress
Easy uses 4×4 grids with addition and subtraction cages. Normal uses 5×5 grids and adds multiplication and exact division. Hard uses 6×6 grids with larger cages. The generator may split cages into smaller clues when needed to preserve a single solution. These are size and operation levels, with no time limit.
Daily changes at midnight UTC, with the same puzzle for everyone choosing the same level. Practice supplies a new grid through New game. Your entries, notes and playing time save separately for each mode and level in this browser. Returning to the page resumes progress when saving is available.
Arrow keys move between cells. Digits enter values, N toggles notes, and Backspace, Delete or 0 erases. Enter checks the grid. On a phone, tap a cell and use the compact keypad. Daily completions update your streak and practice calendar; the fastest-time record uses games completed without hints.
Frequently Asked Questions
Are there 3×3 Sudoku boxes?
No. Calcudoku uses row, column and arithmetic cage rules. A cage outline does not create an additional all-different box.
Which way do I subtract or divide?
Use the larger of the two digits minus the smaller, or divide the larger by the smaller. Division targets are exact whole-number quotients.
Can numbers repeat in one cage?
Yes, provided the repeated numbers occupy different rows and columns and still satisfy the cage target.