Killer Sudoku online
Play Killer Sudoku online with cage sums, combination tools and guided practice. Choose a difficulty, race a ghost or play with friends.
Choose easy, medium, hard or expert in the game selection. You decide when to start.
How the rules work
Normal sudoku rules apply: 1–9 once in every row, column and box. Dashed cages add a rule: their digits must add up to the small total. A digit can never repeat within a cage, even when it crosses a box boundary.
Worked example
A two-cell cage with total 4 must contain 1 and 3. The alternative 2 + 2 is ruled out because a digit cannot repeat within a cage. Use rows, columns and boxes to determine their order.
How is Killer different from classic Sudoku?
Killer keeps the row, column and box rules and adds cage totals and a rule against repeated digits inside each cage. Combinations tell you which digits fit, while rows, columns and boxes help you place them.
How can I get help?
In free practice you can show candidates and request gradual hints. On mobile, open the guide from the input dock. Lessons explain a technique through smaller exercises before you use it on a full puzzle.
Choose how to play
Daily puzzles
Each day offers four difficulties per variant. Play the daily challenges, build a streak and compare times on the leaderboard. You can begin as a guest; an account lets you save your results.
Ghost Race
Race a recording of a player’s first attempt on a puzzle you have not played, when one is available, or race the computer. Choose a difficulty and ghost tempo. Watch the opponent’s progress while solving your own board.
Multiplayer with friends
Choose a variant and difficulty, create a room and share its room link. Race on individual boards, solve together in Co-op or play team against team. Automatic matchmaking finds players with the same variant and difficulty, for both classic Sudoku and Killer.
Free practice with hints
Practise without ranking or a race clock. The guide first reveals a technique, then its supporting cells and finally the full reasoning. Show candidates or let the guide apply a step. Practice boards are not saved when you leave the page.