Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Minutes per zone per watering day
40.0
Weekly minutes per zone
120
Total system minutes per day
160
Gallons per week
5760
Water cost per week
$31.68
Cost per 26-week season
$824
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter weekly water target (in).
- 2Enter sprinkler precipitation rate (in/hr).
- 3Enter watering days per week.
- 4Enter number of zones.
- 5Enter flow per zone (gal/min).
- 6Enter water price per 1,000 gal ($).
- 7Read your minutes per zone per watering day on the right — it updates as you type.
- 8Hit Share to keep the scenario or send it to someone.
About this calculator
Most lawns want about 1 inch of water per week. Run time depends on your sprinkler precipitation rate, not on how green the grass looks after five minutes.
Worked example
Using the values the calculator loads with:
Inputs
- Weekly water target: 1 in
- Sprinkler precipitation rate: 0.5 in/hr
- Watering days per week: 3
- Number of zones: 4
- Flow per zone: 12 gal/min
- Water price per 1,000 gal: 5.5 $
Results
- Minutes per zone per watering day: 40
- Weekly minutes per zone: 120
- Total system minutes per day: 160
- Gallons per week: 5,760
- Water cost per week: $31.68
- Cost per 26-week season: $824
What each field means
Inputs
- Weekly water target (in)
- The weekly water target used in the calculation, measured in in. Starts at 1 in so you have a working example on load. Accepted range: 0.1–3 in.
- Sprinkler precipitation rate (in/hr)
- The sprinkler precipitation rate used in the calculation, measured in in/hr. Starts at 0.5 in/hr so you have a working example on load.
- Watering days per week
- The watering days per week used in the calculation. Starts at 3 so you have a working example on load. Accepted range: 1–7.
- Number of zones
- The number of zones used in the calculation. Starts at 4 so you have a working example on load.
- Flow per zone (gal/min)
- The flow per zone used in the calculation, measured in gal/min. Starts at 12 gal/min so you have a working example on load.
- Water price per 1,000 gal ($)
- The water price per 1,000 gal used in the calculation, measured in $. Starts at 5.5 $ so you have a working example on load.
Results
- Minutes per zone per watering day
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Weekly minutes per zone
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total system minutes per day
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Gallons per week
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Water cost per week
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cost per 26-week season
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the sprinkler run time & water cost calculator work?
Most lawns want about 1 inch of water per week. Run time depends on your sprinkler precipitation rate, not on how green the grass looks after five minutes. The underlying maths is: Minutes = target inches ÷ precipitation rate per hour × 60 ÷ cycles.
What do I need to enter?
6 values: weekly water target, sprinkler precipitation rate, watering days per week, number of zones, flow per zone, and water price per 1,000 gal. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the minutes per zone per watering day result mean?
It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Sprinkler Run Time Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/sprinkler-run-time
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/sprinkler-run-time" target="_blank" rel="noopener">Sprinkler Run Time Calculator — RevenueLab</a> (2026).</p>
Source: [Sprinkler Run Time Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/sprinkler-run-time) (2026).