How it works
Find the area of a circular sector and its arc length. The central angle is entered in degrees from 0 to 360.
A = πr²θ/360; arc = 2πrθ/360
Worked example
Show example inputs and result
Radius: 5 · Central angle: 90.
- Area
- 19.63495408
- Arc length
- 7.85398163
Questions and answers
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.
Method reviewed: October 8, 2026 · Methods & accuracy