Circle Area Calculator

Circle Area Formulas

Key formulas:

  • Area = π × radius²
  • Area = π × (diameter/2)²
  • Area = circumference² / (4π)
  • Sector Area = (angle/360°) × π × radius²
  • Arc Length = (angle/360°) × 2π × radius

Note: For precise calculations, this calculator uses the mathematical constant π (pi) rather than the approximation 3.14. Enter an angle less than 360° to calculate sector area and arc length.