Sprinkler Head Coverage & Spacing Calculator

Calculate the coverage area per sprinkler head, recommended head spacing, and the total number of heads required to irrigate a rectangular zone.

Sprinkler Throw Radius (ft)

Sprinkler Arc Angle (degrees)

Head-to-Head Overlap Factor (%) Industry standard is 50% (head-to-head coverage). Higher % = more overlap.

Zone Length (ft)

Zone Width (ft)

1. Coverage Area per Head (sector of a circle):

A = (arc° / 360) × π × r²

Where r = throw radius (ft), arc° = sprinkler arc angle.

2. Recommended Head Spacing:

S = 2 × r × (1 − overlap / 100)

At the industry-standard 50% overlap: S = r (head-to-head spacing equals the radius).

3. Number of Heads per Row / Column:

n_L = ⌈Zone Length / S⌉ n_W = ⌈Zone Width / S⌉

4. Total Heads:

N = n_L × n_W

5. Actual Spacing (evenly distributed):

S_actual_L = Zone Length / n_L S_actual_W = Zone Width / n_W

Head-to-head coverage (50% overlap) is the industry standard recommended by the Irrigation Association (IA) and Rain Bird. It ensures uniform distribution uniformity (DU ≥ 0.70).
Coverage area is calculated as a circular sector: A = (arc/360) × π × r².
For precipitation rate (in/hr), use: PR = (96.25 × GPM) / S² once flow rate per head is known (Hunter Industries, 2023).

Read Next