Sprinkler Spacing Calculator
Enter the dimensions of your irrigation area and select your sprinkler head type to calculate the number of heads needed, recommended spacing, total GPM demand, and the number of irrigation zones required.
How to Use This Calculator
- Measure your irrigation area. Enter the length and width of the area you want to cover. For irregular shapes, break them into rectangular zones and calculate each separately.
- Select your sprinkler head type. Spray heads are best for smaller areas and tight spaces. Rotary/rotor heads cover larger areas more efficiently and have lower precipitation rates, which reduces runoff on slopes.
- Choose your overlap setting. Head-to-head overlap is always recommended — it ensures uniform coverage with no dry spots. The 50% overlap option spaces heads farther apart and is suitable only for low-pressure budgets where some unevenness is acceptable.
- Review the zone count. If your total GPM exceeds 12, you will need multiple zones. Each zone runs independently on your controller and requires separate wiring and valves.
- Use the pipe estimate as a rough planning figure. Add 15–20% for fittings, elbows, and route variations when purchasing pipe.
How Sprinkler Spacing Is Calculated
- Spacing (head-to-head):
Spacing = Sprinkler Radius - Spacing (50% overlap):
Spacing = Radius × 1.5 - Columns:
CEILING(Length ÷ Spacing) - Rows:
CEILING(Width ÷ Spacing) - Total Heads:
Rows × Columns - Zones Needed:
CEILING(Total GPM ÷ 12)
Pro Tips
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Recommended Irrigation Products
Rain Bird 5000 Series Rotor Sprinkler — 4-pack
Adjustable arc rotor for large lawn areas.
View on Amazon →Hunter PGP Ultra Rotor — 6-pack
Heavy-duty gear-drive rotor with adjustable radius.
View on Amazon →Rain Bird 1800 Series Pop-Up Spray Head — 12-pack
Fixed-arc spray head for small turf and garden beds.
View on Amazon →Orbit 3/4" Anti-Siphon Valve
Backflow prevention valve for in-ground irrigation zones.
View on Amazon →Frequently Asked Questions
What is head-to-head sprinkler coverage?
Head-to-head coverage means each sprinkler head is spaced exactly one radius apart so that its spray reaches the adjacent sprinkler head. For example, a head with a 10 ft radius would be spaced 10 ft from its neighbor. This provides 100% overlap and is the industry standard for uniform watering.
How many GPM does a typical home water supply provide?
Most residential 3/4" water meters supply 10–15 GPM at adequate pressure (40–60 PSI). To be safe, this calculator limits each zone to 12 GPM. If your supply is lower, limit each zone to 10 GPM and add more zones accordingly.
What is the difference between spray heads and rotary heads?
Spray heads (pop-up fixed-spray) deliver water quickly at a high precipitation rate — good for small areas. Rotary (rotor) heads rotate and throw water farther at a lower precipitation rate — better for larger turf areas and slopes where runoff is a concern.
How deep should I bury irrigation pipe?
In warm climates, 6–8 inches deep is sufficient. In freeze-prone climates, bury pipe at least 12 inches below the frost line. Always check local code requirements. Use Schedule 40 PVC for main lines and flexible poly for lateral lines to sprinkler heads.