How much water does my lawn need?

Most lawns need about 1 to 1.5 inches of water per week, including rainfall. To convert a target depth into gallons, multiply your area in square feet by the depth in inches by 0.6234, which is the number of gallons in one square foot covered to a depth of one inch.

How long should I run my sprinkler?

Divide your target watering depth by your sprinkler's application rate in inches per hour, then multiply by 60 to get minutes. For example, reaching 1 inch of water at an application rate of 0.5 inches per hour takes 120 minutes.

How long should I run drip irrigation?

Divide the total volume of water needed in gallons by the combined flow rate of your emitters in gallons per hour, then multiply by 60 to get minutes.

Is this irrigation calculator free to use?

Yes, this calculator is completely free, requires no signup, and runs entirely in your browser with no data sent to any server.

Free Instant Estimate

Irrigation Calculator

Find out exactly how much water your lawn or garden needs, how long to run your sprinkler or drip system, and how often to water.

Irrigation Method

Choose how you water, then fill in the details below.

Area to Water (sq ft) Enter a valid area (greater than 0).

Target Watering Depth (inches) Enter a valid depth (greater than 0).

Sprinkler Application Rate (inches per hour — check your sprinkler's spec, typical rotor ≈ 0.5 in/hr) Enter a valid application rate (greater than 0).

Emitter Flow Rate (gallons/hour, typical ≈ 1–2 gph) Enter a valid flow rate (greater than 0).

Number of Emitters Enter at least 1 emitter.

Weekly Water Need (optional, inches — typical lawn ≈ 1–1.5 in/week, to get a watering schedule) Weekly need cannot be negative.

Estimate ready

Water Volume Needed 0.00 gal

Watering Duration 0 min

Water every 0 day(s)

Estimates only. Actual watering needs vary by soil type, climate, grass/plant species, and season.

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Irrigation Calculator

Irrigation Calculator

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