What hose-end sprinkler output means
A hose-end sprinkler connects to whatever pressure and flow your garden hose delivers, rather than to an engineered nozzle rated at a fixed pressure like an in-ground sprinkler head. Because of that, two identical sprinklers on two different properties, or even the same sprinkler on two different faucets, can put down very different amounts of water. "Output" here means the same thing it does for any sprinkler: a depth of water per hour, usually inches per hour in the US or millimeters per hour elsewhere, not a flow rate by itself.
Two things decide that depth. The first is the sprinkler's flow, how many gallons or liters it puts out per minute. The second is the size of the pattern that flow gets spread across. Oscillating sprinklers spray a rectangle; impact, rotary and spike sprinklers spray a circle or part of one. The same flow spread over a bigger pattern applies a shallower depth per hour, and a smaller pattern applies a deeper one. If you'd rather skip the geometry, a short catch-cup test measures the depth directly, no flow or area math needed.
This calculator is part of the site's sprinkler calculators, and works out application rate and run time from whichever of those two starting points you have.
How this calculator works
The calculator finds your sprinkler's application rate one of two ways, then uses that rate to work out how long it takes to apply a target depth.
1. From flow rate and pattern size
Coverage area
Rectangle: Area = Length × Width
Circle: Area = π ÷ 4 × Diameter²
Or enter the coverage figure printed on the sprinkler's box directly.
Application rate, US units
Rate (in/hr) = 96.3 × Flow (gpm) ÷ Area (sq ft)
96.3 is the constant Rain Bird publishes for converting gallons per minute over square feet into inches per hour. The exact value, from 60 min/hr × 231 cu in/gal ÷ 144 sq in/sq ft, is 96.25; 96.3 is the industry-standard rounding, and that is the value this calculator uses.
Application rate, metric units
Rate (mm/hr) = Flow (L/min) × 60 ÷ Area (m²)
One millimeter of water over one square meter is exactly one liter, so this conversion needs no rounded constant.
2. From a catch-cup test
Application rate from a catch-cup test
Rate = Depth collected ÷ Test time (min) × 60
Works the same way in either unit system: inches and minutes give inches per hour; millimeters and minutes give millimeters per hour.
3. Minutes to apply your target depth
Run time
Minutes = Target depth ÷ Application rate × 60
When you're in flow-and-pattern mode, the calculator also multiplies your flow rate by that run time to estimate the water used for one application.
Rounding policy
Application rates and depths are shown to 2 decimal places in US units and 1 decimal place in metric, matching the precision used in the math. Run time is shown in minutes and hours. Water volume is a downstream estimate, so it's rounded to a sensible figure and shown with "about."
When this calculator isn't the right tool
It only finds an application rate and a single run time. Use a different tool for:
- Total time to water a whole lawn by moving a hose-end sprinkler around several positions. See the hose watering time calculator.
- A full uniformity check across many catch cans in one zone, rather than a single averaged reading. See the catch-can test calculator.
- In-ground zones with fixed heads and spacing. See the sprinkler precipitation rate calculator and sprinkler run time calculator.
- How much water your whole lawn needs this week, before you decide on a target depth. See the lawn watering calculator.
Hose-end sprinkler output calculation example
An oscillating sprinkler's pattern is measured at 25 ft by 20 ft while it's running. A 5-gallon bucket held at the same faucet setting fills in about 37.5 seconds, and the owner wants to apply 1 inch.
- Flow rate: 300 ÷ 37.5 sec = 8 gpm.
- Coverage area: 25 ft × 20 ft = 500 sq ft.
- Application rate: 96.3 × 8 ÷ 500 = 1.5408, shown as 1.54 in/hr.
- Time to apply 1 in: 1 ÷ 1.5408 × 60 = 38.94 minutes, shown as about 39 min.
- Water used: 8 gpm × 38.94 min ≈ 311.5 gal, shown as about 310 gallons.
The same calculation in metric, with a circular pattern
An impact sprinkler wets a 10 m diameter circle. A flow test shows 15 L/min, and the target depth is the metric default of 25 mm:
- Coverage area: π ÷ 4 × 10² = 78.54 m².
- Application rate: 15 × 60 ÷ 78.54 = 11.459, shown as 11.5 mm/hr.
- Time to apply 25 mm: 25 ÷ 11.459 × 60 = 130.85 minutes, shown as about 2 hr 11 min.
- Water used: 15 L/min × 130.85 min ≈ 1,962.75 L, shown as about 1,960 liters.
The circle covers nearly six times the rectangle's area for a similar flow order of magnitude, which is why pattern shape and size change the run time so much even when flow rates look similar.
Measuring your sprinkler's output
Both paths into this calculator start with a short measurement in your own yard, since a package rating rarely matches what a sprinkler does on your hose, at your pressure.
Measuring flow rate
University of California Cooperative Extension describes timing how long a hose or sprinkler takes to fill a 5-gallon bucket, then dividing 300 by that time in seconds to get gallons per minute. For example, a bucket that fills in 30 seconds is a 10 gpm flow. Run the hose at the same tap setting, length and nozzle you'll actually water with, since a longer hose or a partly closed tap lowers the reading.
Measuring pattern size
Turn the sprinkler on at that same setting and measure the wetted area with a tape measure: length and width for a rectangular pattern, or diameter for a circular one. If the sprinkler's box states a coverage area, you can enter that instead, but a measured pattern is usually more accurate, since real coverage often falls short of the printed figure at typical residential pressure.
Running a catch-cup test
University of Arizona Cooperative Extension's Water Wise program and University of California Cooperative Extension both describe the same basic test for hose-end sprinklers: set out several straight-sided containers, such as tuna or cat-food cans, spaced evenly through the spray pattern, then run the sprinkler for a fixed time, 15 minutes in the Arizona guide and 20 minutes in the California one. Measure the depth in each container with a ruler and average the readings; that average, divided by the test time and multiplied by 60, is your application rate. Enter the average depth and the run time above and the calculator does that division for you.
Both guides note that a difference of more than about 15 to 20 percent between containers usually means uneven coverage rather than a bad reading; check for a clogged, misaligned or worn nozzle before trusting the average. The University of California guide also recommends keeping the pressure and flow as consistent as possible between waterings, since output that varies from one session to the next makes any single test less useful for scheduling.
Common mistakes
- Using the box rating instead of measuring. Printed flow and coverage figures assume a specific pressure that your home may not deliver.
- Testing at a different setting than you'll water with. A wide-open tap during the test but a partly closed one at watering time gives a rate you won't actually get.
- Testing on a windy day. Wind pushes spray off the intended pattern and lowers the catch-cup readings.
- Not repeating the test after a nozzle change. Sediment and wear change a nozzle's discharge over a season.
Check local rules first. Many water utilities set specific days, hours or duration limits for hose-end sprinklers. Where those apply, they take priority over any run time calculated here.
What changes your hose-end sprinkler's output
The flow and pattern you measure today can shift for several reasons, which is why it's worth re-checking output occasionally rather than relying on one reading all season.
| Factor | Effect on output | What to adjust |
|---|---|---|
| Water pressure at the tap | Lower pressure reduces both flow and how far the sprinkler throws water. | Measure flow and pattern at the pressure you actually water with. |
| Hose length and diameter | Longer or narrower hoses lose more pressure to friction, cutting flow. | Test with the exact hose you'll use, not a spec sheet. |
| Nozzle wear or clogging | Sediment and wear change discharge gradually over a season. | Repeat the flow or catch-cup test periodically. |
| Pattern width setting | A wider setting on an oscillating sprinkler spreads the same flow thinner. | Measure the pattern at the setting you'll actually run. |
| Overlap between positions | Gaps between sprinkler moves leave dry strips; too much overlap wastes water. | Space new positions at the edge of the previous pattern. |
| Wind | Blows spray off the intended pattern and lowers catch-cup readings. | Test and water on calm days, ideally early morning. |
The overlap guidance above follows University of California Cooperative Extension's tips for hose-end sprinklers, which also suggest using several smaller sprinkler positions rather than one large one for more even coverage. For a numeric check on evenness across many positions or a full zone, the distribution uniformity calculator and catch-can test calculator go further than the single averaged reading used here.
If your calculated rate is much higher than the soil can absorb, water pools and runs off before it soaks in. USDA NRCS lists typical steady-state infiltration rates of about 0.04–0.2 in/hr for clayey soils, 0.2–0.4 in/hr for loam, and more than 0.4 in/hr for sandy and silty soils, shown on the scale above next to your calculated rate. If your rate sits well above your soil's typical range, split the run time into shorter cycles with a break in between; the cycle and soak calculator works out that split, and the soil infiltration rate chart has fuller ranges by texture.
Frequently asked questions
How much water does a hose-end sprinkler put out?
It depends entirely on your hose's flow rate and how large an area the sprinkler spreads that flow over, so there's no single answer. The same flow spread over a bigger pattern applies a lower depth per hour, and a smaller pattern applies more. The most reliable way to find your own output is to measure your flow rate and pattern size, or run a short catch-cup test, both of which this calculator turns into an application rate in inches (or millimeters) per hour.
How much water does an oscillating sprinkler put out?
An oscillating sprinkler sprays a rectangular pattern, so its output depends on your hose's flow rate divided by the length and width of that rectangle, the same way any hose-end sprinkler's output is calculated. Two oscillating sprinklers can apply very different amounts of water even at the same flow rate if one is set to a narrower pattern than the other. Enter your flow rate and the pattern's length and width above to get your sprinkler's actual application rate.
How do I measure my hose's flow rate?
Time how long it takes to fill a 5-gallon bucket from the hose, running it the same way you normally water. University of California Cooperative Extension gives the flow rate as 300 divided by the fill time in seconds, so a bucket that fills in 30 seconds is a 10 gallon-per-minute flow. Repeat the test if the first reading looks off, since kinks or a partly open tap can throw it off.
How do I run a catch-cup test for a hose-end sprinkler?
Set out several straight-sided containers, such as tuna cans, spaced evenly through the sprinkler's spray pattern, then run the sprinkler for 15 to 20 minutes, the run time used by University of Arizona and University of California Cooperative Extension guides. Measure the depth of water in each container with a ruler and average the readings. Multiply that average by 60 divided by your test's run time in minutes to get inches (or millimeters) per hour, or enter the depth and run time above and this calculator will do it for you.
Why do two sprinklers with the same flow rate apply water at different rates?
Application rate is flow divided by the area it covers, so the size of the wetted pattern matters as much as the flow itself. A sprinkler that throws water over 300 square feet applies roughly twice the depth per hour as one throwing the same flow over 600 square feet. That's why the pattern size you measure, not just the sprinkler's flow rating, has to go into the calculation.
How long should I run my hose-end sprinkler to apply 1 inch?
Divide 1 inch by your sprinkler's application rate, then multiply by 60 to get minutes. For example, a sprinkler applying 1.5 inches per hour takes about 40 minutes to apply 1 inch. Enter your own application rate, or the flow and pattern details that calculate it, above to see the run time for your setup.
Does water pressure affect my sprinkler's output?
Yes. Lower pressure reduces both the flow rate through the hose and how far a sprinkler throws water, which changes its pattern size, so a drop in pressure changes the application rate in two ways at once. Measuring your flow rate and pattern at the pressure and hose length you actually use, rather than relying on a package rating, accounts for this automatically.
What if my catch-cup depths vary a lot between containers?
A difference of more than about 15 to 20 percent between containers, the threshold used in University of California and University of Arizona Cooperative Extension guides, usually points to uneven coverage rather than a measurement error. Check for clogged or misaligned nozzles, low pressure, or wind pushing the pattern to one side. Averaging uneven readings still gives a usable application rate, but the actual depth on your lawn will vary more than that average suggests.
For a numeric uniformity score across a full zone, see the catch-can test calculator or the distribution uniformity calculator.
Who built and checked this calculator
Licensed Professional Engineer and Irrigation Association Certified Irrigation Designer with more than 20 years in irrigation design, system auditing and landscape water management. Full profile
How this page was checked
- Formulas, unit conversions and both worked examples verified by hand.
- Precipitation-rate formula checked against Rain Bird's published equations.
- Catch-cup test method checked against University of Arizona and University of California Cooperative Extension guides.
Sources
- Rain Bird Corporation. Precipitation Rate Equations.
- University of Arizona Cooperative Extension, Water Wise Program. Lawn Watering Guide for Cochise County.
- Hartin, Janet S., and Donald R. Hodel. University of California Cooperative Extension. Lawn Watering Guide.
- Schwankl, Lawrence J., Terry L. Prichard, and Blaine R. Hanson. University of California Agriculture and Natural Resources. Soil Intake Rates and Application Rates in Sprinkler-Irrigated Orchards (ANR Publication 8216).
- USDA Natural Resources Conservation Service. Soil Infiltration.