Circle Sector Area Calculator

Enter the circle's radius and central angle in degrees to find the area covered by that sector.

Results rounded to two decimals.

Examples

  • r = 5, angle = 90° ⇒ 19.63
  • r = 3, angle = 45° ⇒ 3.53
  • r = 10, angle = 30° ⇒ 26.18

FAQ

What angle unit is used?

Degrees. Convert from radians if needed.

What if the angle is 360°?

The area equals that of the full circle.

Can the angle be more than 360°?

Yes, but it represents multiple rotations, giving areas beyond one circle.

Additional Information

  • Formula: A = πr² × (θ ÷ 360).
  • The result uses the same unit squared as the radius input.
  • Widely used in geometry, engineering, and design for partial circle areas.

Related calculators

Contextualize sectors with ISO 80000-2

Circular sectors share the plane-angle notation described in the standard. Dive deeper into symbol rules and dimensionless quantities by visiting the ISO 80000-2 guide.