How it works
Find the area between two concentric circles. The inner radius cannot exceed the outer radius.
A = π(R²−r²)
Worked example
Show example inputs and result
Outer radius: 5 · Inner radius: 3.
- Area
- 50.26548246
Questions and answers
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.
Method reviewed: October 8, 2026 · Methods & accuracy