Count the union of overlapping circular measured areas.
Are two circular bed or surface areas sharing a region?
Use the matching calculator
Use this decision sequence
- Measure each circle’s radius and the distance between centres.
- Check whether they are disjoint, partly overlapping or one contains the other.
- Subtract the shared region once from the sum of circle areas.
- Use an annulus model only for a complete inner-circle exclusion rather than a two-circle union.
Keep the quantities distinct
| Quantity or assumption | How to use it |
|---|---|
| Disjoint circles | Their areas add directly. |
| One contained circle | The union is the larger circle. |
| Partial intersection | Requires the circular lens deduction. |
Worked comparison
Two illustrative radius-1 m circles sharing the same centre have combined union area π m², not 2π. If their centres are 2 m apart, they only touch and their union is 2π m². Between those cases, the shared lens changes continuously with centre separation; treating every overlap as a full inner circle would be wrong.
Check before using the estimate
The circular assumptions must match the actual measured boundaries; overlap does not change a supplied layer depth.
All dimensions, product properties, prices and specifications in this example are illustrative arithmetic inputs. Use the values from your measured plan, selected product data sheet and supplier quote. This guide does not choose construction specifications or certify safety.
Calculation and scope checked 2026-10-04. Methods and scope.