💧 Irrigation Calculator

How Long to Run Your Sprinklers — Exactly

Calculate exactly how long to run your system to hit your weekly watering target.

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Calculate Your Run Time

Enter your lawn size, water target, and sprinkler output to get a precise run time per session.

💡 Don't know your sprinkler output? Do a catch-cup test: place an empty tuna can in your spray zone, run sprinklers for exactly 15 minutes, then measure the water depth in the can (inches). Multiply by 4 to get inches per hour.
Run Time per Session
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Lawn Care 101

Not Sure How Often to Water?

Before you calculate runtimes, make sure you're watering at the right frequency. The deep and infrequent guide explains why 2–3 sessions a week beats daily watering every time — and what signs to watch for if you're over or underwatering.

Read the Watering Guide →
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Gear & Tips
What You'll Need
My Spreader Pick
Top Pick
ECHO RB-60 Heavy-Duty Broadcast Spreader
“The spreader I use on my own lawn — nothing else comes close.”
  • 60 lb hopper — covers up to 25,000 sq ft per load
  • Factory-calibrated spread pattern up to 8 ft wide
  • Maintenance-free gear case — no grease, no hassle
  • Foot-operated side deflector keeps product off driveways & beds
  • 10" pneumatic tires handle any terrain with ease
  • Powder-coated steel frame — 5-year consumer warranty
Check Price & Availability →
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My Sprinkler Pick
Top Pick
Melnor XT Metal Turbo Oscillating Sprinkler with Flow Control
“Best sprinkler I've ever owned — covers the whole yard and I can dial it in exactly where I want it.”
  • Covers up to 4,500 sq ft — 20 precision nozzles for even, consistent coverage
  • TwinTouch controls independently adjust width and range — keep water off the driveway
  • Zoom control shrinks or expands the watering zone for precise coverage
  • Infinity Turbo Drive delivers smooth, puddle-free oscillation
  • Metal construction built to last — backed by a Limited Lifetime Warranty
  • Rated best oscillating sprinkler by Wirecutter
Check Price & Availability →
Affiliate link — I earn a small commission at no extra cost to you. I only recommend gear I personally use.

Watering Basics

Most lawns need 1–1.5 inches of water per week. Water deeply and infrequently rather than a little every day — this encourages deep root growth. Early morning watering reduces evaporation and fungal disease risk.