Rainfall & Irrigation Calculator
Calculate lawn irrigation needs based on rainfall, lawn size, and target watering. See weekly water deficit, watering time, and cost.
Inputs
sq ft
inches
in/week
in/hour
Results
Water Deficit
0.5 in/week
Watering Time20 minutes
Gallons Needed/Week1,558
Est. Monthly Cost$31.15
Water Deficit
0.5 in/week
How to Use This Calculator
- Start by filling in the input fields below. Results update instantly as you type, so you can experiment with different values to see how they affect the outcome.
- Lawn Area — Total lawn area. Accepts values from 100 sq ft to 100,000 sq ft (default: 5,000 sq ft).
- Weekly Rainfall — Average weekly rainfall. Accepts values from 0 inches to 10 inches (default: 0.5 inches).
- Target Watering — Most lawns need 1-1.5 inches per week. Accepts values from 0.5 in/week to 3 in/week (default: 1 in/week).
- Sprinkler Rate — Sprinkler water output rate. Accepts values from 0.1 in/hour to 5 in/hour (default: 1.5 in/hour).
- Once all inputs are set, review your results in the Results panel. Here's what each output means:
- Water Deficit — shown as a numeric value. This is the primary result of this calculator.
- Watering Time — shown as a numeric value.
- Gallons Needed/Week — shown as a numeric value.
- Est. Monthly Cost — shown as a dollar amount.
- Explore the related calculators below if you need deeper analysis or want to approach this topic from a different angle.
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