Circle Calculator
Know any one measurement; recover all four.
Circle solved
r = 5
- Diameter
- 10
- Circumference
- 31.41593
- Area
- 78.53982
How the Circle Calculator works
The calculation follows the standard method used across the US — no shortcuts, no hidden assumptions. Here is exactly what happens behind the scenes:
Frequently Asked Questions
How does the Circle Calculator work?
Enter your numbers above and results update instantly using standard formulas, computed entirely on your device.
Is the Circle Calculator free to use?
Yes — completely free with no signup required, and it works on phones, tablets, and desktops.