This annulus area calculator helps when outer radius, inner radius are already known and you want the area quickly.
Informational calculator only. Verify important outputs independently before legal, tax, medical, engineering, safety-critical, contractual, employment, or compliance use.
Enter job values, review the estimate, then use the decision hints before ordering or quoting.
area = pi x (outer radius^2 - inner radius^2)Subtract the smaller circle area from the larger one to get the ring-shaped area.
The outer radius should be larger than the inner radius.
This page is tuned for clean geometry checks during drafting or homework around annulus inner circumference.
Next: annulus outer circumference.
Find the area of any circle given its radius.
Keep more decimal places when the result will be reused in another formula, drawing, or comparison rather than read once and rounded.
Yes. The formula is stable and this tool only covers straightforward calculation.