Annulus Area Calculator
Find the area of a ring or washer, the space between two concentric circles, from the outer and inner radius. Enter outer radius and inner radius to…
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Find the area of a ring or washer, the space between two concentric circles, from the outer and inner radius. Enter outer radius and inner radius to see area when you calculate.
Worked example
Example calculated from the starting values. Enter your own values and press Calculate to get your result.
With the default inputs (outer radius = 10, inner radius = 6), the results are: area 201.062.
Quick reference: outer radius vs result
Reference table based on the example values; it is not your calculation result.
| Outer radius | Area |
|---|---|
| 5 | -34.558 |
| 10 | 201.062 |
| 20 | 1,143.540 |
| 50 | 7,740.884 |
| 100 | 31,302.829 |
| 200 | 125,550.609 |
Frequently asked questions
What formula does this calculator use?
Area = pi × (R^2-r^2). Variables: R = outer radius, r = inner radius.
What do I need to enter?
You need outer radius, inner radius. Results update as you type.
What is an example result?
With the default inputs (outer radius = 10, inner radius = 6), the results are: area 201.062.
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