Sprinkler System Calculator

Plan your lawn irrigation system with accurate head counts, zone calculations, and pipe estimates. Enter your lawn area, water supply details, and sprinkler type to get a complete system layout with material quantities.

Enter System Details

Lawn Area (sq ft)

Sprinkler Head Type

Available Flow Rate (GPM)

Water Pressure (PSI)

Estimated Main Line Run (feet)

Head Spacing Strategy

Full System Estimate

Sprinkler Heads

Coverage per Head

GPM per Head

Heads per Zone

Number of Zones

Zone Valves

Main Line Pipe

Lateral Pipe (est.)

How to Use This Calculator

Enter your total lawn area in square feet.
Select your sprinkler head type — rotors for large areas, sprays for small/narrow areas.
Enter your available GPM (do a bucket test: fill a 5-gal bucket and time it).
Enter water pressure in PSI (check with a pressure gauge on your hose bib).
Click "Calculate" for head counts, zones, and pipe estimates.

The Formulas

Heads = Lawn Area ÷ Coverage per Head

Heads per Zone = Available GPM ÷ GPM per Head

Zones = Total Heads ÷ Heads per Zone

Typical Values

Rotor heads: ~1,200 sq ft coverage, 2–4 GPM each (30' radius head-to-head)
Spray heads: ~200 sq ft coverage, 1–2 GPM each (12' radius head-to-head)
Drip: ~1 sq ft per emitter at 12" spacing, 0.5–1 GPH each