Lawn Watering Calculator
Most lawns do well with about an inch of water a week, counting rain. Enter how much water the lawn needs and how fast your sprinkler puts it down, and this gives the run time.
- Free
- Works offline after your first visit
- Saves on this device
- No sign-up
- Updated
How it works
Run time is the depth of water needed divided by the depth the sprinkler puts down each hour. That gives hours, which are shown as hours, minutes and seconds.
Splitting the weekly total into several sessions lets water soak in instead of running off. Divide the weekly time by the number of sessions to get each run.
Worked example
A lawn that needs 1 in of water a week, with a sprinkler that puts down 0.75 in an hour, runs 40 min each session.
Questions
How do I measure my sprinkler's output?
Set out several straight-sided cans in the spray for an hour, then measure the depth in each and average them. That depth per hour is the rate to enter.
Should I count rain?
Yes. Count rainfall toward the weekly need. A rain gauge or an empty can shows how much fell.
Is morning better for watering?
Early watering loses less to evaporation, and the grass dries before evening. Many lawn guides suggest it.
More like this
- Lawn Fertilizer CalculatorProduct weight from the label rate.
- Acre CalculatorAcres from the length and width of a plot.
- Farm Loan CalculatorPayment and total interest on a farm loan.
- Average Daily Gain CalculatorWeight gained per day between two weighings.
- Chicken Feed CalculatorFeed amount, cost and cost per dozen eggs.
- Drip Irrigation CalculatorEmitter count and total flow for rows.