Arc Length Calculator
Arc length, sector area, chord and segment from radius and central angle.
The four pieces of a circle slice
The arc is the curved edge: r × θ (angle in radians), or θ/360 of the full circumference. The sector is the whole pizza slice: θ/360 of the circle's area. The chord is the straight line between the arc's ends: 2r sin(θ/2). The segment is what's left of the slice after cutting off the triangle: r²(θ - sin θ)/2.
Radians earn their keep here
Arc length is the reason radians exist: measure the angle in radians and the arc is just radius times angle, no conversion factor. 60° is π/3 ≈ 1.047 radians, so a radius-10 arc is 10.47 units long.