Use this arc length calculator to find the length of a circular arc from its radius and central angle.
Arc length calculator
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Using the calculator
Enter the Radius and Angle of your arc. The calculator instantly computes the arc length along with the full circle's dimensions. Switch between degrees and radians with the angle unit dropdown.
What is arc length?
An arc is a portion of a circle's circumference. Arc length is the distance along that curved section – imagine straightening out the curve and measuring it with a ruler.
Arc length formula
Arc length depends on the radius and central angle:
s = r \theta
Where s is the arc length, r is the radius, and θ is the central angle in radians. For degrees, use s = (θ/360) × 2πr.
