Diameter to Radius Calculator

Your details

Choose which value you want the calculator to find.
All outputs use the same unit.
The full width of the circle passing through its centre.
cm
Radius
5

Half the diameter

Diameter10
Circumference31.415927
Area78.539816
_unitLabelcm
_unitLabelSqcm²

Radius is 5 cm, diameter is 10 cm.

  • Circumference of the circle: 31.4159 cm (the distance all the way around the edge).
  • Area enclosed by the circle: 78.5398 cm² (the flat surface inside the boundary).
  • Diameter is always exactly twice the radius: d = 2r, so radius is always exactly half the diameter: r = d/2.

Next stepTo find the volume of a sphere with the same measurement, use the formula V = (4/3) x pi x r³.

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