Circle Calculator
Calculate all properties of circles from radius, diameter, circumference, or area. Find arc length, sector area, chord length, and more with precise calculations.
Circle Calculator
Circle Properties
Radius
10.000 cm
r = 10.000
Diameter
20.000 cm
d = 2r = 20.000
Circumference
62.832 cm
C = 2πr = 62.832
Area
314.159 cm²
A = πr² = 314.159
Unit Conversions
Millimeters (mm): 100.000 mm
Centimeters (cm): 10.000 cm
Meters (m): 0.100 m
Inches (in): 3.937 in
Feet (ft): 0.328 ft
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What is Circle Calculator?
A circle calculator helps you find all properties of circles using any single measurement. Whether you know the radius, diameter, circumference, or area, this calculator can determine all other measurements using fundamental circle formulas based on π (pi).
Circle Properties
- Radius: Distance from center to any point on the circle
- Diameter: Distance across the circle through the center (2 × radius)
- Circumference: Distance around the circle (2π × radius)
- Area: Space inside the circle (π × radius²)
Advanced Properties
- Arc Length: Distance along the circumference for a given central angle
- Sector Area: Area of a slice of the circle for a given central angle
- Chord Length: Straight-line distance between two points on the circle
- Segment Area: Area between a chord and the arc
Key Formulas
- Circumference: C = 2πr = πd
- Area: A = πr²
- Arc Length: L = (θ/360°) × 2πr
- Sector Area: A = (θ/360°) × πr²
FAQ - Circle Calculator
π (pi) is a mathematical constant approximately equal to 3.14159. It represents the ratio of a circle's circumference to its diameter. This ratio is the same for all circles, regardless of size, making π fundamental to all circle calculations.