Easy Killer Sudoku

Cage sums meet classic Sudoku logic. Digits in each cage must total the clue — no repeats allowed. Free, no login required.

Easy Medium Hard Expert

New to Killer Sudoku? Easy mode uses small cages with only one or two possible digit combinations — the perfect way to learn cage arithmetic. Start here.

Mistakes

0/3

Score

Time

00:00

Try Medium Killer Sudoku →

Progress0%

34 cages All Killer Sudoku →

How to play Killer Sudoku

The board starts with pre-filled digits as clues. Your clues are the cage sums (small numbers in cell corners). Fill each cage so the digits sum to that total, with no repeats within any cage. All standard Sudoku rules still apply (1–9 in every row, column and 3×3 box).

How to Play Killer Sudoku →

Killer Sudoku - Complete Guide

Difficulty Overview

Level	Given digits	Cages	Avg. solve time
Easy	~26	~28-32	5-10 min
Medium	~18	~30-36	10-20 min
Hard	~8	~34-40	20-40 min
Expert	0	~36-45	40-90 min

Cage Sum Limits

Cage size	Min sum	Max sum	Forced?
1 cell	1	9	Yes (unique)
2 cells	3	17	At extremes
3 cells	6	24	At extremes
4 cells	10	30	At extremes
5 cells	15	35	At extremes
9 cells	Always 45		Yes

Forced cage combinations you must memorise

2-Cell cages - Forced sets

Sum	Only possible set
3	{1, 2}
4	{1, 3}
16	{7, 9}
17	{8, 9}

3-Cell cages - Forced sets

Sum	Only possible set
6	{1, 2, 3}
7	{1, 2, 4}
23	{6, 8, 9}
24	{7, 8, 9}

Key solving techniques

45 Rule

Every row, column, and 3x3 box sums to 45. If all cages in a row are known except one cell, the missing value = 45 - (sum of all other cage totals in that row). This is the single most powerful Killer technique.

Easy tip - Start every puzzle by scanning for forced cages (sums of 3, 4, 16 or 17 in 2 cells). These give you free digits immediately. Then apply the 45 rule to any row or column where only one cage cell is unknown.

Frequently Asked Questions

Can digits repeat in a cage?

No - Every cage follows the no-repeat rule. Each digit appears at most once within any single cage.

What is the 45 rule?

Every row, column, and 3x3 box contains digits 1-9, summing to 45. Subtracting known cage sums within any unit reveals leftover cell values.

Is Killer Sudoku harder than Classic?

Generally yes - There are no given digits, so you rely entirely on cage arithmetic and elimination. Easy Killer is roughly equivalent to Medium Classic.

What is Killer Sudoku?

Difficulty

★★★☆☆

3/5

Constraint Type

Cage Sums

Typical Givens

0 (all cages)

Avg. Solve (Easy)

8 min

Solving Techniques for Easy Level

Technique	Description	Level
Cage Sum Elimination	Each cage has a fixed sum. Use the sum and the number of cells to calculate which digits are possible — e.g. a 2-cell cage summing to 3 can only be {1,2}.	Beginner
No-Repeat Rule	Digits cannot repeat within a cage. Combined with sum constraints, this eliminates many candidates immediately.	Beginner

Ready to go deeper? Try Medium Killer Sudoku to unlock Intermediate techniques.

Techniques to Master at Easy

Last Possible Number technique — Two-cell cages totalling 3, 4, 16, or 17 have exactly one digit pair — intersect that pair with the cell's row and box and the cage often resolves outright.
Notes in Sudoku — Write cage combinations as your notes, not generic 1–9 marks — a 3-cell cage of 7 is only {1,2,4}, and noting that once beats re-deriving it every scan.
Last Remaining Cell technique — Cage maths bans digits from whole cages at a time — a 3-cell cage totalling 8 can never contain a 9 or an 8 — so a digit's last legal cell in its box emerges quickly.

Average Solve Time by Difficulty

Easy

8 min

Medium

18 min

Hard

38 min

Expert

70 min

Want a full walkthrough of rules, strategies, and solving steps? How to Play Killer Sudoku →

Related Variants

Little Killer Sudoku

Keeps the sum-clue arithmetic but moves it onto diagonals where digits may repeat — a deliberate twist on your cage instincts.

Sandwich Sudoku

Another sum-driven puzzle: instead of cage totals you deduce which digits sit between the 1 and the 9 in each row and column.

Arrow Sudoku

Swaps cages for arrows whose shaft must add up to the circled digit — the same combination-counting muscle in a linear shape.

Frequently Asked Questions — Easy Killer Sudoku

What is Killer Sudoku?

Killer Sudoku combines standard Sudoku with arithmetic cage clues. The grid is divided into dashed cages, each with a target sum. Digits in each cage must sum to that number and cannot repeat within the cage. Standard Sudoku rules also apply — every row, column, and 3×3 box must contain 1–9 exactly once.

How do I start an easy Killer Sudoku?

Start with cages that have only one valid combination. A 2-cell cage summing to 3 can only be {1,2}. A 2-cell cage summing to 17 can only be {8,9}. These force-filled cages give you placements without any guessing. Then use the 45 Rule on rows and boxes to find further easy deductions.

What is the 45 Rule?

Every row, column, and 3×3 box contains the digits 1–9, which always sum to 45. If you add up all the cage totals that sit entirely within one unit (row, column, or box), the remainder tells you the sum of any cage cells that cross the boundary. These leftover cells — called innies or outies — often resolve to a single digit at easy difficulty.

Can digits repeat within a cage?

No. Unlike Arrow Sudoku arrows or Little Killer diagonals, Killer Sudoku cages do not allow repeated digits. Every cage cell must hold a different digit. Combined with the cage sum, this severely restricts which combinations are possible — and is what makes small extreme-sum cages immediately solvable.

How is Easy Killer Sudoku different from harder levels?

Easy puzzles have more single-combination cages and generous 45 Rule deductions that resolve cells quickly. Harder levels introduce longer cages with many possible combinations and require tracking innies and outies across multiple intersecting units simultaneously.

More questions? See the full Killer Sudoku FAQ.