Loading…

How to use Arc Length Calculator

Enter the radius and the central angle and the calculator returns the arc length and the sector area with formulas shown.

Frequently asked questions

How is arc length calculated?

Arc length = r × θ when θ is in radians, or (θ/360) × 2πr when θ is in degrees.

What is the sector area formula?

Sector area = (θ/360) × πr² in degrees, or ½ × r² × θ in radians.

Do I enter the angle in degrees or radians?

You can use degrees — the calculator handles the conversion and shows both the arc length and sector area.

More Math Calculators

Golden Ratio Calculator
Golden dimensions from one measurement.
Coordinate Line Properties
Slope, distance, midpoint, and equation together.
Circle Calculator
Full circle report from radius, diameter, circumference, or area — solves all four properties at once with formulas.
Triangle Solver (SSS)
Solve a triangle from three sides: Heron area, perimeter, all three interior angles, and equilateral/isosceles/scalene type.
Sphere Calculator
Sphere volume, surface area, diameter, and great-circle circumference from the radius with exact formulas.
Cylinder Calculator
Cylinder volume, base area, lateral surface, and total surface area from radius and height with formulas.
Cone Calculator
Cone volume, slant height, lateral surface, base area, and total surface area from radius and height.
Ellipse Calculator
Ellipse area, Ramanujan perimeter, eccentricity, and focal distance from the two semi-axes.
Regular Polygon Calculator
Regular polygon interior/exterior angle, perimeter, apothem, area, and circumradius from side count and length.
Trapezoid Calculator
Trapezoid area, median (midsegment), and perimeter from the two parallel sides, height, and legs.
2D Vector Calculator
Magnitude, dot product, 2D cross (scalar), sum, and angle between two 2D vectors.
3D Vector Calculator
Magnitudes, dot product, cross product vector, and angle between two 3D vectors.

← View all Math CalculatorsBrowse all 1,100+ tools →