CLASSIC SUDOKU
A place for every number.
Fill every row, column, and 3×3 box with the digits 1–9, without repetition. Keep track of possibilities with candidate notes, and turn careful elimination into a clear answer.
Quidoku · MADE FOR iPHONE
A little quiet.
A better puzzle.
From the first small discovery to the final square. Make room for focused thinking with Classic Sudoku, Killer Sudoku, and reasoning you can follow.
No ads · No separate account · Core play works offline
2Classic and Killer modes
6Difficulty levels to explore
DailyA fixed Classic challenge
PLAY / A PUZZLE AT YOUR PACE
A familiar grid. A fresh way to think.
Follow the rows, columns, and boxes, or bring cage totals into the picture. Pick your mode, then choose a difficulty that feels right.
KILLER SUDOKU
Let the numbers add up.
Keep the Classic rules, then add a new connection: digits in each dashed cage must be distinct and add up to its total. Bring arithmetic and logic together.
Six levels: Beginner · Easy · Medium · Hard · Expert · Evil
LEARN / FOLLOW THE REASONING
See the next step. Understand why.
When you get stuck, follow the evidence. Turn a helpful hint into something you can recognize on your own next time.
Follow each step
Logical hints use board highlights and written explanations. Review the reasoning before deciding whether to place the target digit.
Keep your thinking visible
Separate number rows handle answers and candidates. Use Auto Notes, Undo, coloring, and drawing to organize more involved patterns.
Put a lesson into practice
Illustrated lessons meet hands-on exercises. Learn a technique, then place a digit or remove candidates to check your understanding.
EVERY DAY / MAKE ROOM TO THINK
A small break. A satisfying puzzle.
Practice a little, explore a technique, or pick up where you left off. There is room to find your own rhythm.
A daily challenge
Each day brings a fixed Classic puzzle. Core games and lessons also work offline, so practice can fit into your day.
Pick up where you left off
Unfinished games, notes, and drawings are saved locally. Return through game history and explore your results in game statistics.
Bring a puzzle from paper
Puzzle analysis can recognize large digits in a standard Sudoku photo on your device. Check the recognized board against the original before reviewing the steps.
Make the board your own
Choose from six themes, switch languages, and adjust sound, haptics, and mistake checking to suit the way you like to play.
Quidoku
Take your time with the next one.
Want to get started, use hints, or manage your progress? The help page covers common actions and questions.