Circle Geometry Calculator

Compute arc length, chord length, sector area, and segment area from radius and central angle. Visualize the results with an interactive diagram.

Inputs

units
Use any unit (cm, m, in). Results use the same unit.
0 < angle ≤ 360 for meaningful results.
0°
Enter radius > 0 and 0 < angle ≤ 360.

Results

Arc length

—
L = r · θ, with θ in radians

Chord length

—
c = 2r · sin(θ/2)

Sector area

—
A = ½ r² θ

Segment area

—
Aseg = sector − ½ r² sin(θ)

Formulas Used:

Arc Length = r × θ (θ in radians)
Chord Length = 2 × r × sin(θ/2)
Sector Area = ½ × r² × θ
Segment Area = Sector Area - ½ × r² × sin(θ)
θ is the central angle in radians for the formulas. This tool converts degrees to radians automatically.

Diagram

Sector Arc Chord Radii