Math Calculators
Circle Calculator
Calculate circle area, circumference, and diameter from radius.
Result
--What does this calculator do?
Calculate circle area, circumference, and diameter from radius.
Formula
Circle area = πr² and circumference = 2πr.
Example calculation
A radius of 5 gives area about 78.54.
Common use cases
- Geometry
- Design
- Measurement
Limitations and accuracy notes
This calculator is for quick planning and education. Results depend on your inputs and may not include every real-world rule, fee, tax, health factor, or local requirement.
Circle Calculator FAQ
Is this calculator free?
Yes. It gives quick estimates directly in your browser.
Should I use this as professional advice?
No. Use it as a planning aid and confirm important decisions with a qualified professional.