Killer Sudoku: today's puzzle
Today's puzzle
Loading ยท the grid and its level
(a small spoiler)
Checked: exactly one solution, reachable by logic. The level is the hardest technique our solver needed, not the grid size.
Settings
Rule breaks (a repeated digit) always show in red. "Show mistakes" also marks cells that disagree with the solution.
Fill the 9x9 grid so every row, column and 3x3 box contains 1 to 9 once. Dashed cages add a second rule: their digits add up to the small sum in the corner, and never repeat inside the cage. Every daily puzzle has exactly one solution.
The rules in three lines
- Every row, column and 3x3 box contains the digits 1 to 9 once each.
- The digits in each dashed cage add up to the number in its corner.
- A digit never repeats inside a cage.
Killer sudoku is also called sum sudoku, and some puzzle books and apps print it as Sudoku Killer. If you already play sudoku online, killer is the variant to try next: the same grid, plus sums. Full rules and a worked example.
Today's levels and our bank
Each day has 4 Killer Sudoku puzzles, one per level below. The bank covers 512 days, from 16 October 2026 to 10 March 2028, and every one of its 2,398 puzzles was checked for a single solution by a separate program before it shipped.
| Daily puzzle | Size | Days in the bank | Median steps | Hardest technique, most often (share) |
|---|---|---|---|---|
| Easy | 9x9 | 512 | 146 | Cage combinations (100%) |
| Medium | 9x9 | 512 | 160 | Rule of 45 (100%) |
| Hard | 9x9 | 512 | 172 | Rule of 45 on several houses (99%) |
| Expert | 9x9 | 512 | 180 | Contradiction (100%) |
Source: the Gridaday bank, 2,048 puzzles of Killer Sudoku graded by our solver; data as of 2026-10-17.
The rule of 45
Every row, column and box adds up to 45. Take a row, subtract the cages that lie entirely inside it, and what is left is the sum of the few cells that belong to cages sticking out of it. It is the single most useful idea in killer sudoku, and our Medium puzzles cannot be finished without it.
How our Easy killer works
Without a single revealed digit, even a gentle killer usually needs the rule of 45. So our Easy puzzles use small cages and reveal a few digits, as given digits or as one-cell cages: then cage combinations and singles are enough, and the rule of 45 waits for Medium.
Questions
Why are some digits already filled in on Easy?
Without any revealed digit, even a gentle killer usually needs the rule of 45. Revealing a few, as given digits or as one-cell cages, lets Easy rely on combinations alone.
How do I see a cage's combinations?
The killer sudoku combinations page lists them all and has a calculator with included and excluded digits.
Do notes count as mistakes?
No. Only placed digits are checked, and only when you press Check or turn on "Show mistakes".
Is this killer sudoku free?
Yes: free killer sudoku online, four new puzzles a day, plus the archive, unlimited play and printable sheets, with no account and nothing to buy.
Is there a daily killer sudoku site with every level?
This is one: Easy, Medium, Hard and Expert every day, the same four for everyone, so you can compare times with a friend.