Venn counts & inclusion–exclusion

Have counts, not lists? Calculate every region.

Enter exact region counts or inclusive intersections. Venn.dev derives the union, none, probabilities, and a consistent 2–4 set diagram.

Ready

01 · input

Enter the counts you know

Sets

2 sets 3 sets 4 sets

What the fields mean

Exact regions Intersections

Exact regions

Enter mutually exclusive regions such as “A only” and “A ∩ B only.” Their sum is the union.

Set namesUsed in the diagram and exports

Exact region countsEvery person or item belongs to one field.

Universe size optional When supplied, the calculator also finds “none of the sets” and probabilities.

Examples

Consistent counts Union calculated

Every exact region is non-negative.

Counts are exact. Shape areas are illustrative, not proportional.

03 · inspect

Exact arithmetic.Intersection mode uses inclusion–exclusion / Möbius inversion and blocks negative derived regions.

Local-only.Counts, names, projects, and share fragments are processed in this browser.

Use the matching tool.Use the Maker when you have member lists; use UpSet when you have more than four sets.