Circle Diameter to Area Calculator



Calculate Area of Circle
Diameter (ø) [?]
Select diameter unit nanometres (nm) micrometres (µm) thousands of an inch (thou) 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 thous (thou²) 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.