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⭕ Circle & Arc Calculator

Enter a circle radius and central angle to compute diameter, circumference, area, arc length, sector area, and chord length.

Circle & Arc Calculator

Connect radius, diameter, circumference, circle area, arc length, sector area, and chord length. Enter a radius and central angle to see all related circle measurements.

Inputs

Radius

Central angle (degrees)

Use any length units you like (cm, m, inches) as long as you are consistent. Angles are in degrees.

circle calculatorarc length calculatorsector area calculator

Circle summary

Radius

Diameter

Circumference

31.415927

Circle area

78.539816

Arc & sector

Angle (degrees)

Angle (radians)

1.047198

Arc length

5.235988

Sector area

13.089969

Chord length

Quick relationships

Circumference = 2πr
Area = πr²
Arc length = rθ (θ in radians)
Sector area = ½r²θ (θ in radians)
Chord length = 2r sin(θ/2)

How to use this tool

Enter the radius of your circle in any units.
Set a central angle in degrees for the arc or sector you care about.
Use the outputs to plug into geometry problems or construction planning.

Circle calculator for geometry homework

Instantly connect radius, diameter, circumference, and area.
Solve arc length and sector area questions without re-deriving formulas.
Use chord length to work with inscribed shapes and structural spans.

What this circle & arc calculator supports

Any positive radius and angle in degrees.
Unit-agnostic outputs: use centimeters, meters, inches, or feet consistently.
Fast conversions between degree and radian angles.

FAQ

Can I input diameter instead of radius?: Yes. If you know the diameter, divide it by 2 and enter that as the radius. All results then use that implied radius.
Are angles always in degrees?: Inputs expect degrees, but the calculator also shows the equivalent in radians for use in formulas.
Can I copy these values into other tools?: Yes. Combine the outputs with other ToolHop calculators like area/volume or triangle solvers for more complex geometry problems.

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