Sprinkler Zone Capacity Calculator
Enter measured supply flow and up to three nozzle groups. The result adds each group's demand, applies a visible reserve, and shows whether the planned zone fits the measured flow.
- Measured supply
- 12.0 GPM
- Safe zone flow
- 9.6 GPM
- Total nozzle demand
- 10.0 GPM
A passing result does not prove adequate pressure. Long pipe runs, elevation, restrictions, and mixed head types can still cause poor coverage.
How to use the result
Available GPM is not the same as operating pressure. A positive flow margin cannot rule out pressure loss from long pipe runs, elevation, restrictions, or a partially open valve. Use the exact manufacturer nozzle chart at the pressure measured in the zone.
Why nozzle groups are more accurate
Real zones often contain different arcs or nozzle sizes. Six heads at 1.5 GPM is not the same demand as four 1.5 GPM heads plus two 3.0 GPM heads. Add each rated-flow group separately and keep sprays, rotors, and drip equipment on hydraulically compatible zones.