How to use the circle sector and arc calculator
Compute arc length and sector area from a central angle. Enter radius, central angle in the fields above; the arc length, sector area, chord length are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- r — Radius
- th — Central angle (°)
Worked example
With radius = 10, central angle = 60 °, the calculator gives arc length ≈ 10.47198; sector area ≈ 52.35988; chord length ≈ 10.
Frequently asked questions
What is the formula for the circle sector and arc calculation?
Arc length = π × r × th / 180. Sector area = π × r × r × th / 360. Chord length = 2 × r × sin(th / 2). Here r is radius, th is central angle (°).
What inputs do I need for the circle sector and arc calculator?
You need radius, central angle in °. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.