Lawn Watering Calculators
Work out how much water your lawn needs, how long to run your sprinklers, when to water, and how to water new seed and sod. Each calculator answers one question, shows its formula, and works in US or metric units.
Which lawn calculator do you need?
Find your question below. Each calculator does one job, so picking the right one gets you a precise answer.
| Your question | Use this calculator | How it works |
|---|---|---|
| How much water does my lawn need this week, after rain? | Lawn Watering Calculator | Uses a weekly target, such as about 1 inch, minus rainfall. |
| How many minutes should I run my sprinklers? | How Long to Water Lawn Calculator | Minutes per session from your sprinkler type and soil. |
| How much water does my lawn use, based on local weather? | Lawn Water Requirement Calculator | Uses reference evapotranspiration (ETo) and a turf coefficient. |
| Which days should I water, and when should I start? | Lawn Watering Schedule Calculator | Turns a weekly amount into a day-by-day plan. |
| How much water does my type of grass need? | Grass Type Water Needs Calculator | Compares bermuda, zoysia, fescue, bluegrass and more. |
| I just seeded or laid sod. How should I water it? | Grass Seed Watering Calculator | Frequent, light watering until roots establish. For sod, use the sod watering calculator. |
| How much water does my lawn use in a month or season? | Lawn Water Usage Calculator | Totals from your controller program or weekly depth. |
| I water with a hose. How long will it take? | Lawn Hose Watering Time Calculator | Time and sprinkler moves from your hose flow. |
| My lawn went through a dry spell. How much should I catch up? | Lawn Water Deficit Calculator | Shortfall over the dry period and a recovery plan. |
| How many gallons is an inch of water on my lawn? | Inches of Water to Gallons Calculator | Converts depth over an area to gallons or liters. |
All lawn calculators
Everyday watering
- Lawn Watering CalculatorWeekly water to apply after rain, in gallons or liters
- How Long to Water Lawn CalculatorMinutes per session by sprinkler type and soil
- Lawn Watering Schedule CalculatorWhich days, how many cycles and when to start
- Lawn Hose Watering Time CalculatorTime and sprinkler moves to water a lawn by hose
Water needs and water use
- Lawn Water Requirement CalculatorTurf water use from local ETo and grass type
- Grass Type Water Needs CalculatorCompare water needs of lawn grass species
- Lawn Water Usage CalculatorMonthly and seasonal gallons used on your lawn
- Lawn Water Deficit CalculatorHow far behind your lawn is after a dry spell
- Inches of Water to Gallons CalculatorConvert water depth over an area to volume and back
Lawn watering basics
What university extension research says, in brief. Each calculator page goes into detail and cites its sources.
About 1 inch a week is a starting point
Extension services commonly use about 1 inch (25 mm) per week, from rain and irrigation together, for established lawns. Rutgers Cooperative Extension notes lawns may need up to 1¾ inches in hot, dry, windy weather, and much less when it's cool.
Water deeply and less often
Iowa State University Extension recommends a single weekly application, or two applications three or four days apart, rather than frequent light watering that keeps roots shallow.
Soil sets the frequency
Clemson Cooperative Extension suggests about 1 inch in one watering on heavy clay, about ½ inch twice a week on sandy to loamy soils, and about ⅓ inch three times a week on very sandy soils.
Grass type matters
In a University of California field study, warm-season grasses such as bermudagrass needed 36 percent less water than cool-season grasses for acceptable quality. UC uses crop coefficients of 0.8 for cool-season and 0.6 for warm-season turf.
Local watering restrictions always come first. For the data behind these numbers, see lawn watering by grass type, the sprinkler precipitation rate chart and the soil infiltration rate chart.
Related calculator categories
- Sprinkler calculatorsPrecipitation rates, zones, spacing and audits
- Scheduling and ET calculatorsEvapotranspiration, water requirements and budgets
- Garden and tree calculatorsBeds, vegetables, containers, trees and shrubs
- Soil calculatorsWater holding capacity and infiltration
- Cost and savings calculatorsIncluding what your lawn watering costs
- All calculatorsEvery irrigation calculator by category
Sources and review
This page and its calculators are reviewed by Daniel Reeves, PE, CID. Last reviewed . See our methodology and editorial policy, or report an error.
- Rutgers Cooperative Extension. Best Management Practices for Watering Lawns (FS555).
- Iowa State University Extension and Outreach. What is the proper way to water a lawn?
- Clemson Cooperative Extension, Home & Garden Information Center. How Often Should A Lawn Be Watered?
- Harivandi, M. A., et al. (2009). Managing Turfgrasses during Drought. University of California ANR Publication 8395.