Math

Arc Length Calculator

Length of a circular arc.

Enter your values

Results update instantly as you type — no submit needed.

Results
Arc length
10.0531
Angle in radians
1.25664
Sector area
40.2124
Chord length
9.4046
Full circumference
50.2655

Quick answer

Arc length equals the radius times the central angle in radians.

s = r × θ (θ in radians)

How to use the Arc Length Calculator

  1. 1Enter the circle's radius.
  2. 2Enter the central angle.
  3. 3Pick degrees or radians.

Frequently asked questions

How do I convert degrees to radians?

Multiply by π/180.

What if the angle is a full circle?

The arc length becomes the circumference, 2πr.