| Metric | Value | Copy |
|---|---|---|
| System | {{ system_type }} | |
| Precipitation rate | {{ precip_rate_value }} {{ precip_rate_unit }} | |
| Zone flow (GPH) | {{ zone_flow_gph.toFixed(2) }} GPH | |
| Days per week | {{ days_per_week }} | |
| Net depth / event (in) | {{ net_depth_event_in.toFixed(3) }} | |
| Gross depth / event (in) | {{ gross_depth_event_in.toFixed(3) }} | |
| Gallons / event (gross) | {{ event_gallons.toFixed(2) }} | |
| Runtime / event (min) | {{ runtime_per_event_minutes.toFixed(2) }} | |
| Runtime / week (min) | {{ (runtime_per_event_minutes*days_per_week).toFixed(2) }} | |
| Cycle/soak | {{ cycles }} × {{ cycle_minutes.toFixed(1) }} min, soak {{ soak_minutes }} min | |
| Gallons / event (gross) | {{ event_gallons.toFixed(2) }} | |
| Gallons / week (gross) | {{ (event_gallons*days_per_week).toFixed(1) }} |
Irrigation runtime is the amount of time a zone needs to run so the landscape actually receives the intended water depth or water volume. That matters because minutes that are too short can leave plants stressed, while minutes that are too long can waste water and push runoff past what the soil can absorb.
This calculator converts water demand into minutes per event for either sprinkler or drip irrigation. It can start from reference evapotranspiration and a crop coefficient, from a direct target depth per sprinkler event, or from a direct weekly gallons target for drip. The result package then shows runtime per event, runtime per week, gallons where area is known, and a cycle-and-soak plan when sprinkler application outruns infiltration.
A common use case is a lawn or shrub zone that needs a quick schedule check before you update a controller. Another is comparing two very different delivery systems. A spray zone is usually understood in inches per hour, while a drip zone is understood in emitter flow and total gallons. The tool keeps those paths separate so the runtime math stays readable.
The boundary is that this is not a weather service, a soil-water balance model, or a municipal compliance checker. You supply the evapotranspiration, crop coefficient, area, and system performance assumptions yourself. If those assumptions are weak, the final minute value can still look precise while resting on uncertain inputs.
This package is a planning aid for irrigation scheduling and does not replace a site audit, local watering rules, or professional design review.
Choose the irrigation method that matches how the zone is measured in real life. If you know the sprinkler precipitation rate, stay in sprinkler mode. If you know emitter flow and how many emitters are on the zone, use drip mode. That choice determines whether the package thinks in water depth or in delivered gallons.
For weather-driven scheduling, enter reference evapotranspiration as either inches per day or inches per week and then scale it with a crop coefficient. If you already know the application target more directly, the package can skip that step: sprinklers can use a target depth per event, and drip zones can use a weekly gallons target instead.
The area field is optional only in some paths. It is needed whenever you want gallons estimated from water depth, and it is essential for the drip ETo method because the tool has to convert weekly plant water demand into a weekly gallon requirement. If you do not know drip area, the practical fallback is to switch to the direct weekly gallons method.
Advanced controls change interpretation in different ways. Application efficiency and DU factor increase gross water applied above the net plant demand. Infiltration rate and soak time matter only for sprinkler mode, where they decide whether the total runtime should be split into multiple shorter cycles.
Net depth / event and Gross depth / event before blaming the precipitation rate. Efficiency and DU factor often explain the difference.Watering Timeline to see exactly how the runtime is split and how long the soak break lasts.The calculator runs in the browser and this tool bundle does not ship a server-side helper. It converts all irrigation math into a small set of canonical units first: precipitation and infiltration to inches per hour, area to square feet, and drip flow to gallons per hour. After that, sprinkler and drip paths diverge.
In sprinkler mode, the tool first computes net water depth per event. If you choose the weather path, weekly plant water use is computed as weekly reference evapotranspiration multiplied by crop coefficient and then divided by irrigation days per week. If you choose the direct depth path, that target depth becomes the net requirement immediately. The package then inflates that net depth by the application efficiency and DU factor to get gross depth, converts gross depth into hours from the precipitation rate, and finally converts hours into minutes.
In drip mode, the package computes total zone flow from emitter flow multiplied by emitter count. Weather-based drip scheduling converts weekly plant water demand into gallons with the standard 0.623 gallons per square foot per inch factor. Direct weekly gallons mode skips the evapotranspiration step entirely. In both cases, the tool divides the gross weekly gallons by irrigation days and then divides each event by total zone flow to get runtime in minutes.
| Path | What the tool uses | What it returns |
|---|---|---|
| Sprinkler + ETo | ETo, crop coefficient, days per week, precipitation rate, efficiency, and DU factor | Net depth, gross depth, runtime per event, runtime per week, and gallons if area is known |
| Sprinkler + target depth | Target depth per event instead of ETo and crop coefficient | Runtime and gross application for a chosen depth without weather math |
| Drip + ETo + area | ETo, crop coefficient, irrigated area, emitter flow, emitter count, efficiency, and DU factor | Gross gallons per event, runtime per event, runtime per week, and total zone flow |
| Drip + weekly gallons | A direct weekly gallons target instead of ETo and area | Runtime from the demanded gallons and the zone's total drip flow |
The DU control deserves one clarification. In irrigation auditing, distribution uniformity is usually expressed as a lower-quarter percentage or fraction. This package does not ask for raw DULQ. It asks for a DU factor with a neutral value of 1.0, and higher numbers lengthen runtime to compensate for uneven application. In other words, it is a package-specific multiplier inspired by uniformity losses, not the audit metric itself.
Cycle-and-soak logic is also explicit. When a positive infiltration rate is entered and sprinkler precipitation exceeds that rate, the tool computes a maximum single-cycle duration as 60 × (infiltration / precipitation) × 0.8. If the total event runtime exceeds that ceiling, the package splits the total into equal cycles and inserts the chosen soak period between them. Drip mode does not use this runoff-splitting rule.
The result package extends beyond the summary. Irrigation Metrics includes copyable values and table exports, Depth Overview compares net and gross application in a bar chart, Watering Timeline turns cycle-and-soak into a running-versus-soaking timeline, and JSON captures both the inputs and the derived results for reuse outside the page.
Use the calculator in one clean pass from delivery method to controller-ready minutes. The goal is to keep the chosen method consistent with the data you actually know.
System type as Sprinkler or Drip.ETo + Kc when you have weather demand, Target depth per event when you already know the sprinkler depth goal, or Weekly gallons when you already know the drip volume goal.Advanced for application efficiency, DU factor, and, in sprinkler mode, infiltration rate and soak minutes.Irrigation Metrics, Depth Overview, Watering Timeline, and JSON before exporting the run.Runtime / event is the number most people eventually send to a controller. Runtime / week is the total watering burden after multiplying by the number of irrigation days. The difference between net and gross application shows how much extra runtime the package adds to cover the efficiency and uniformity assumptions.
If the summary shows a cycle count, it means the entered sprinkler precipitation rate is higher than the entered soil infiltration rate and the total runtime is long enough to be split. That split is not a weather calendar. It is a runoff-control schedule for one event, expressed as equal runtime blocks separated by the chosen soak interval.
Net depth / event and Gross depth / event means the runtime is being driven more by efficiency assumptions than by plant demand alone.Gallons / event (gross) is the central quantity. If you use the weather path without area, the package has no way to turn water depth into gallons, so you should switch methods or add area.This package intentionally stops short of a full soil-water balance. It does not pull live weather, subtract recent rainfall, estimate root-zone storage, or check watering-day restrictions. Use it to translate assumptions into minutes, then compare those minutes with local conditions and controller rules before treating the schedule as final.
A straightforward sprinkler schedule. Leave the defaults in sprinkler mode: 1.5 inches of weekly ETo, crop coefficient 0.7, three irrigation days per week, and a 1.5 in/hr precipitation rate. The tool computes 1.05 inches of weekly plant water use, 0.35 inches net depth per event, and about 14.0 minutes per event. With a 400 square foot area entered, the run also estimates about 87.2 gross gallons per event.
The same zone with lower effective performance. Keep the same sprinkler setup but change application efficiency to 70 percent and DU factor to 1.15. Gross depth rises to about 0.435 inches, runtime increases to roughly 17.4 minutes per event, and the package splits the schedule into two cycles of about 8.7 minutes each because the entered 0.5 in/hr infiltration rate is lower than the 1.5 in/hr application rate.
A direct drip schedule from gallons. Switch to drip mode, keep 30 emitters at 1 GPH, choose Weekly gallons, enter 50 gallons per week, and set two irrigation days per week. The package calculates 25 gross gallons per event and a runtime of about 50 minutes per event because the zone delivers 30 gallons per hour. This is the simplest path when you already know the weekly gallon target but not the irrigated area.
No. You enter ETo and crop coefficient yourself. The package translates those values into runtime, but it does not pull location data, rainfall, or live forecasts.
It is a compensation multiplier, not a raw lower-quarter DU percentage. A value of 1.0 is neutral. Higher values lengthen runtime to reflect poorer uniformity.
That happens only in sprinkler mode when you enter a positive infiltration rate lower than the precipitation rate and the total runtime exceeds the tool's single-cycle limit. The split is meant to reduce runoff by letting water soak in between cycles.
No. Sprinkler target-depth runs can produce minutes without area. But area is needed for gallon estimates and for the drip weather path that converts evapotranspiration into total gallons.
No calculation endpoint is bundled for this tool. The summary, charts, exports, and JSON payload are created in the browser after the page loads.
No. It is a runtime-planning aid. Field pressure, nozzle performance, soil variability, slope, rainfall shutoff rules, and municipal schedules still need to be checked separately.