Geometry

Annulus Area

Area of a ring between two radii.

Formula

Formula
A = π (R2 − r2)

Variables

SymbolDefinitionType & rangeUnitsRole
R outer radius real number (ℝ) input
r inner radius real number (ℝ) input

Try it yourself

Interactive calculator
Result

Worked examples

Example 1
Givenouter R = 5, inner r = 3
Result50.26548246
Example 2
Givenouter R = 10, inner r = 9
Result59.69026042