Measure the length of a circular arc, the curved distance along part of a circle, from the radius and the central angle. In radians the arc length equals the radius multiplied by the angle theta, written as L equals r times theta, and this tool converts your degree input to radians for you. For a radius of 10 and a 90 degree angle, the arc length is about 15.71 units, one quarter of the full circumference. The calculator also shows the chord length, the straight line across the ends of the arc, so you can compare the curved and straight distances. Arc length matters in road design, gears, pulleys, sports tracks and any curved path. Enter the radius in any unit and the angle in degrees, and the arc length returns in your chosen linear unit. All math is local to your browser at full precision with instant copy.
Arc length is the radius times the central angle in radians, often written r times theta.
You enter the central angle and the tool converts as needed so the arc length comes out in the same unit as the radius.
Arc length follows the curve of the circle while a chord is the straight line between the two endpoints, so the arc is longer.
Measure the length of a circular arc, the curved distance along part of a circle, from the radius and the central angle. In radians the arc length equals the radius multiplied by the angle theta, written as L equals r times theta, and this tool converts your degree input to radians for you.
Yes. Arc Length Calculator is completely free, with no sign-up and no usage limits.
Yes. Arc Length Calculator runs in any modern web browser. There is nothing to download or install.
Yes. Arc Length Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.