Cluster Count Solver

Cluster Count Solver — Step by Step

Click a square and type the number in its circle, then press Solve. Or play a generated puzzle and send it here with one click.

Cluster Count Solver: rules, how to use it, tips

Shade squares so every circled number equals the total size of all the shaded groups touching that circle.

Circled squares are never shaded.
A group is a set of shaded squares joined side by side.
A circle’s number is the total number of squares in all the groups that touch it along a side.
Squares without circles may be shaded or white, as the numbers require.

Choose the size and type the circled numbers (or press Sample).
Press Solve and step through: full circles, overflowing groups and forced growth.

Zeros. A 0 means all four neighbours are white.
Full circles. Once the groups around a circle add up to its number, every square that could join them is white.
Overflow. If shading a square would merge groups into too many squares for a nearby circle, it is white.
One way out. A circle that still needs more and can only grow through one square shades it.

The full guide, with a worked example and common mistakes: How to play Cluster Count.

Do diagonal squares count as touching?

No — only squares that share a side.

Can a group touch two circles?

Yes — and its whole size counts for each circle it touches.

Is there always one answer?

Yes — every puzzle here is checked to have exactly one solution.

How do I solve one from a book?

Open the Cluster Count Solver, type the circled numbers and press Solve.