Circle Diameter to Area Calculator



Calculate Area of Circle
Diameter (ø) [?]
Select diameter unit nanometres (nm) micrometres (µm) millimetres (mm) centimetres (cm) inches (in) feet (ft) yards (yd) metres (m) kilometres (km) miles (mi) nautical miles (nmi)
Circle Area [?]
Select area unit sq nanometres (nm²) sq micrometres (µm²) sq millimetres (mm²) sq centimetres (cm²) sq inches (in²) sq feet (ft²) sq yards (yd²) sq metres (m²) acres (ac) hectares (ha) sq kilometres (km²) sq miles (mi²) sq nautical miles (nmi²)

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User Guide

This tool will calculate the area of a circle from the diameter, and will convert different measurement units for diameter and area.

Formula

The formula used to calculate circle area is:

A = π x (ø/ 2)²

Symbols

• A = Circle area
• π = Pi = 3.14159…
• ø = Circle diameter

Diameter of Circle

Enter the diameter or two times the radius of a circle.

Area of Circle

This is the area contained within a circle with the specified diameter.