Circle Area Calculator
The Circle Area Calculator is an online tool that quickly calculates the area of a circle based on radius, diameter, or circumference. This calculator supports multiple unit conversions, including square millimeters, square centimeters, square meters, square inches, and square feet.
Circle Area Calculation Formulas
1. Calculate Area by Radius
Formula: Area = π × Radius²
Expression: S = πR²
2. Calculate Area by Diameter
Formula: Area = π × (Diameter/2)²
Expression: S = πD²/4
3. Calculate Area by Circumference
Formula: Area = Circumference² / (4 × π)
Expression: S = S²/(4π)
Where π is approximately 3.1415926.
How to Use the Calculator
- Enter any one of the values: radius, diameter, or circumference in the input box
- The calculator will automatically calculate the other two values based on the input
- Click the "Calculate" button to get the area of the circle
- Results will be displayed in different units
Application Scenarios
- Circular area calculation in engineering
- Circular area calculation in architectural design
- Circle area demonstration in mathematics education
- Estimation of circular object areas in daily life
Unit Conversion
The calculator automatically converts the calculation results to the following units:
- Square millimeters (mm²)
- Square centimeters (cm²)
- Square meters (m²)
- Square inches (in²)
- Square feet (ft²)