Use this segment area calculator to find the area between a chord and its arc from the radius and central angle.
Segment area calculator
Table of Contents show ▼
Using the calculator
Enter the Radius and Angle of your segment. The calculator instantly computes the segment area along with the full circle's dimensions. Switch between degrees and radians with the angle unit dropdown.
What is a segment?
A segment is the region between a chord and the arc it cuts off. Unlike a sector (pie slice from the center), a segment is bounded by a straight chord on one side and a curved arc on the other.
Segment area formula
Segment area is the sector area minus the triangle formed by the two radii:
A_{segment} = \frac{r^2}{2}(\theta - \sin\theta)Where r is the radius and θ is the central angle in radians.
