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Module · Math · Geometry
Circle Calculator
Enter any one property — radius, diameter, circumference or area — and the calculator solves for the other three instantly.
radius5
diameter10
circumference31.415927
area78.539816
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Guide
How Circle Calculator works
Step 01
Choose what you know
Radius, diameter, circumference or area.
Step 02
Enter the value
Any positive number.
Step 03
Get the other three
Instantly solved from the standard circle formulas.
FAQ
Frequently asked
How precise is π?+
Uses JavaScript's Math.PI — accurate to ~15 significant digits.
Circumference vs perimeter?+
They mean the same thing for a circle — the distance around it.