Drip irrigation flow calculator
Find the flow your rows need, convert a tape specification, or time a bucket test at your water source.
Nominal zone flow
- Tape in this zone
- 4,320 ft
- Rated flow
- 0.22 GPM per 100 ft
- Reference pressure
- 8 psi
Emitter converter
Use the rate and spacing printed on your tape data sheet.
Bucket test
Fill a container from an open outlet and record how long it takes.
How the calculations work
Zone flow in gallons per minute (GPM) is the active tape length divided by 100 ft, multiplied by the tape’s flow per 100 ft at the reference pressure.
To convert an emitter rating, multiply gallons per hour (GPH) by the number of emitters in 100 ft, then divide by 60. For the bucket test, divide the collected gallons by the fill time in seconds and multiply by 60.
Check the manufacturer’s maximum row length and the pressure at the tape inlet with the zone running. See a worked example of the effect of pressure and slope.
Plan the drip lines in a raised bed or calculate how long to run your zone.
Sources
- Rivulis T-Tape US data sheet500 and 700 Series tables, by model number · 2019 · checked
- Toro Aqua-Traxx product specificationsAqua-Traxx flow and filtration tables, by emitter code · ALT046_1 · checked
- Netafim USA agriculture catalogThinwall driplines, SLXF63808.16-12 and nominal flow rates · September 8, 2025, page 18 · checked
- Irritec USA P1 thin-wall dripline specificationsFlow by pressure and spacing, and 1,000-ft flap-outlet reel table · LIT-P1-07/23 · checked
- Colorado State University Extension, Irrigation Run Times with Drip TapeDrip tape specifications and flow units · Web edition · checked
- Utah State University Extension, The Do-It-Yourself Guide to Backyard Drip IrrigationDetermining Available Water (Flow Rate) · Extension guide · checked