How it works
A = πr²; circumference = 2πr
Input definitions
- Radius (units)
- Enter the value in the labeled unit.
A worked example
- Radius (units)
- 3
Area: 28.274333882308138 units²; circumference: 18.84955592153876 units
Assumptions & limits
Uses the stated input units. Results are rounded for display; keep additional precision for subsequent calculations.
Sources & review
Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.
Method updated 2026-10-17. Content checked against the stated method and examples. Our verification approach.
Common questions
Can I check the result before using it?
Compare the worked example with your inputs and use the stated method: A = πr²; circumference = 2πr. Confirm input units and boundary choices before relying on the result.
How does the Circle area and circumference tool work?
A = πr²; circumference = 2πr.
What are the assumptions and limits of Circle area and circumference?
Uses the stated input units. Results are rounded for display; keep additional precision for subsequent calculations.