Calculate the arc length and sector area of a circle from radius and central angle.
| Arc length | – |
| Sector area | – |
Use this calculator to find the arc length and the area of a circular sector from the radius and the central angle in degrees. A sector is a pizza-slice portion of a disk: the region bounded by two radii and the included arc.
The fraction of the full circle is θ / 360. Arc length is that fraction of the circumference 2 π r; sector area is that fraction of π r². A semicircle is 180°; 360° is the whole disk. Angles outside 0–360 still scale the same way (for example 720° is two full turns).
Use any length unit for the radius; the arc is a length in that unit and the area is in that unit squared.
Radius: Radius of the circle.
Central angle (°): Angle at the centre, in degrees.
Arc length: Length of the curved edge of the sector.
Sector area: Area of the pizza-slice region.
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