Would you like to know the area or the circumference of a circle and the only piece of information you have is the diameter of the circle? Use our **Circle Area & Circumference Calculator from Diameter calculator** that gives you the circumference and the area of a circle – the only thing you have to enter is the diameter of the circle.

## Formulas used for the calculation of a circle’s circumference and area from diameter:

- The formula used for the calculation of circumference: C = d ∙ π
- The formula used for the calculation of area: A = (d/2)2 ∙ π