Lawn Watering Calculator
Minutes per zone and gallons to hit 1 inch of water a week.
Enter your values
Enter the lawn area in sq ft.
Enter the water per week in in.
Enter the precipitation rate in in/hr.
Enter the watering days per week you are working with.
Enter the water price per 1,000 gal in $.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Total weekly run time
- 120 minutes
- Per session
- 60 minutes x 2 days
- Water used per week
- 2,492 gallons
- Weekly water cost
- $12.46
- Monthly cost
- $53.95
Working
- 11 in / 0.5 in/hr = 2 hr = 120 min
Quick answer
Run time = target inches divided by the sprinkler precipitation rate. One inch over 1,000 sq ft is about 623 gallons.
minutes = inches / rate x 60; gallons = 0.623 x area x inches
At a glance
| What it does | Minutes per zone and gallons to hit 1 inch of water a week. |
|---|---|
| Category | Home & DIY |
| Inputs needed | Lawn area, Water per week, Precipitation rate, Watering days per week, Water price per 1,000 gal |
| Main output | Total weekly run time |
| Formula | minutes = inches / rate x 60; gallons = 0.623 x area x inches |
| Cost | Free — no sign-up, no download |
How to use the Lawn Watering Calculator
- 1Find your precipitation rate with the tuna-can test: place cans, run 15 minutes, measure depth and multiply by four.
- 2Aim for about 1 inch per week including rainfall.
- 3Water deeply on fewer days to push roots down rather than sprinkling daily.
Inputs explained
- Lawn area(sq ft)
- Enter the lawn area in sq ft.
- Water per week(in)
- Enter the water per week in in.
- Precipitation rate(in/hr)
- Enter the precipitation rate in in/hr.
- Watering days per week
- Enter the watering days per week you are working with.
- Water price per 1,000 gal($)
- Enter the water price per 1,000 gal in $.
Worked example
Using the values the calculator loads with:
Inputs
- Lawn area4000 sq ft
- Water per week1 in
- Precipitation rate0.5 in/hr
- Watering days per week2
- Water price per 1,000 gal5 $
Results
- Total weekly run time120 minutes
- Per session60 minutes x 2 days
- Water used per week2,492 gallons
- Weekly water cost$12.46
- Monthly cost$53.95
- 1 in / 0.5 in/hr = 2 hr = 120 min
Frequently asked questions
Is 1 inch a week right for every lawn?
It is a good default for cool-season grass. Sandy soil wants smaller, more frequent doses; clay wants slow cycles to avoid runoff.
When should I water?
Early morning. Evening watering leaves blades wet overnight and invites fungal disease.
What do I need to enter into the Lawn Watering Calculator?
Just 5 values: lawn area, water per week, precipitation rate, watering days per week, water price per 1,000 gal. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Lawn Watering Calculator work out the answer?
Run time = target inches divided by the sprinkler precipitation rate. One inch over 1,000 sq ft is about 623 gallons. It applies the formula minutes = inches / rate x 60; gallons = 0.623 x area x inches and shows the working so you can check each step by hand.
Is the Lawn Watering Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.