The sprinkler coverage calculator estimates how many sprinkler heads you need and the optimal head-to-head spacing for complete coverage without dry spots.
Sprinkler System Planning Basics
A well-designed irrigation system uses head-to-head spacing as the standard for coverage uniformity. The key principle: if your spray head covers a 12-foot radius, heads should be placed 12 feet apart. This creates overlapping coverage that compensates for wind drift and ensures uniform soil moisture.
Zone planning
Never mix spray heads and rotor heads in the same zone — they have very different precipitation rates (inches per hour), so one or the other will be over- or under-watered. Design separate zones for: lawn (rotors for large areas, sprays for small), drip zones (garden beds), and any areas with significantly different sun/shade exposure.
FAQ
What is head-to-head coverage?
Head-to-head coverage means each sprinkler head's spray radius reaches the adjacent head. This is the standard for adequate coverage — heads are spaced at the same distance as the spray radius, not the diameter. This 100% overlap ensures no dry spots even in windy conditions.
What is the difference between spray heads and rotor heads?
Spray heads (fixed spray pattern, pop-up): coverage radius 5-15 feet, used for smaller areas. Rotor heads (rotating stream): coverage radius 15-45 feet, better for larger lawns. Rotors apply water more slowly (0.4-1 inch/hr) than sprays (1-2 inch/hr), reducing runoff on slopes.
Is this calculator free?
Yes, completely free with no signup required.