What this calculator finds
A chord is a straight line segment connecting two points on a circle. This calculator finds the chord’s length from the circle’s radius and the central angle between the two points.
The formula
Chord length is c = 2r·sin(θ/2), where r is the radius and θ is the central angle in radians (degrees entered here are converted automatically). The perpendicular distance from the circle’s center to the chord (the apothem) is r·cos(θ/2).
This is commonly used in geometry, engineering drawings, and construction layouts involving arcs and circles. This tool is for general educational and planning purposes.
Last reviewed August 2026