Arc Length Calculator | Find Arc Length of a Circle
Calculate the arc length of a circle easily using our online calculator. Just enter the radius and central angle in degrees or radians to find the arc length. Visualize the arc on a circle diagram.
Arc Length (s):
Formula
where s is the arc length, r is the radius, and $$\theta$$ is the central angle in radians.
Understanding Arc Length
Arc length is the distance along the curved line making up the arc. Imagine a slice of pizza; the arc length is the length of the crust on the curved edge. To calculate it, you need the circle's radius (the distance from the center to the edge) and the central angle (the angle formed at the center by the arc's endpoints).
The formula $$ s = r \theta $$ is used, where $$\theta$$ must be in radians. If your angle is in degrees, convert it to radians first by multiplying by $$\frac{\pi}{180}$$. This calculator handles the conversion for you, making it simple to find the arc length whether your angle is in degrees or radians. Arc length is used in geometry, engineering, and anywhere you need to measure along a curve.
Learn more about arc length on Wikipedia.