Drip Irrigation Calculators
Work out how many emitters your plants need, how long to run a drip zone, how far apart to space tubing and emitters, and whether a zone's flow fits your supply, valve and filter. Each calculator answers one question, shows its formula, and works in US or metric units.
Which drip irrigation 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 |
|---|---|---|
| I'm planning a whole drip system for my plants. Where do I start? | Drip Irrigation Calculator | Plant count and type give emitters, total flow, zones and run time. |
| How many drip emitters does each plant need? | Drip Emitter Calculator | Plant type, size and soil give emitter count and GPH. |
| How far apart should emitters be along the tubing? | Drip Emitter Spacing Calculator | Soil type sets lateral spread and spacing along a run. |
| How far apart should parallel drip lines be in a bed? | Drip Tubing Spacing Calculator | Soil type sets row spacing and total tubing length. |
| Will my emitters overload the zone, valve or filter? | Drip Zone Flow Calculator | Total emitter flow checked against supply, valve and filter ratings. |
| How long can I run a drip line before flow gets uneven? | Drip Line Max Length Calculator | Tubing size, emitter flow and inlet pressure set the maximum run. |
| How many minutes should I run my drip system? | Drip Run Time Calculator | Plant water need and emitters × GPH set minutes per session. |
| How fast does my drip grid apply water, in inches per hour? | Drip Precipitation Rate Calculator | Emitter flow and grid spacing convert to in/hr and run time. |
| How wide does the wet area spread from each emitter? | Drip Wetted Area Calculator | Soil type and emitter flow give wetted diameter and area. |
| Are all my emitters putting out about the same amount? | Emission Uniformity Calculator | Catch-can test results give a uniformity rating and run-time fix. |
| How much drip tape and flow do I need for a row crop field? | Drip Tape Calculator | Bed spacing and tape flow give tape length and GPM per acre. |
| How many micro-sprinklers can I run, and how much do they cover? | Micro Spray Calculator | Micro-spray flow and wetted diameter set coverage and count per zone. |
| How long should a bubbler run to fill a tree basin? | Bubbler Flow Calculator | Bubbler GPM and basin volume give fill time and count per zone. |
| How long should I run a soaker hose to water a bed? | Soaker Hose Calculator | Output per foot and hose length give run time for a depth. |
| How many drip emitters does a tree need as it grows? | Tree Drip Emitter Calculator | Canopy or trunk size sets emitter count, placement and run time. |
| What pressure regulator does my drip zone need? | Drip Pressure Regulator Calculator | Supply pressure and zone flow set the required outlet rating. |
| What mesh or micron filter does my drip system need? | Drip Filter Sizing Calculator | Emitter passage size and zone flow set the filter rating. |
All drip irrigation calculators
Plan a drip system
- Drip Irrigation CalculatorPlants to emitters, flow, zones and run time
- Drip Emitter CalculatorPlant type and size to emitter count and GPH
- Drip Emitter Spacing CalculatorSoil type to emitter spacing along the tubing
- Drip Tubing Spacing CalculatorSoil type to row spacing and tubing length
- Drip Zone Flow CalculatorZone flow checked against supply, valve and filter
- Drip Line Max Length CalculatorTubing, emitters and pressure to maximum run length
Run times and application rate
- Drip Run Time CalculatorPlant water need and emitter flow to minutes
- Drip Precipitation Rate CalculatorGrid emitter flow and spacing to inches per hour
- Drip Wetted Area CalculatorSoil and emitter flow to wetted diameter and area
- Emission Uniformity CalculatorCatch-can test to emission uniformity and run-time fix
Emitters for specific setups
- Drip Tape CalculatorBed spacing and tape flow to GPM per acre
- Micro Spray CalculatorMicro-spray flow to coverage, rate and count per zone
- Bubbler Flow CalculatorBubbler flow and basin size to fill time
- Soaker Hose CalculatorOutput per foot and length to run time
- Tree Drip Emitter CalculatorTree size to emitter count, placement and run time
Drip irrigation basics
What university extension research says, in brief. Each calculator page goes into detail and cites its sources.
A well-run system can reach 90% efficiency
Oklahoma State University Extension notes that a well designed and maintained drip irrigation system is capable of an application efficiency of about 90 percent, since water goes to the root zone with little runoff or wind loss.
Aim for even flow across every emitter
Oklahoma State University Extension recommends no more than about 10 percent variation in discharge between the emitters with the lowest and highest output, which is why pipe sizing and run length matter.
Soil texture decides emitter spacing
Oklahoma State University Extension explains that emitter spacing should match how far water spreads sideways in the soil: coarse, sandy soils spread water very little, so emitters need to sit closer together than in finer soils.
Filter fine enough for the smallest passage
University of Florida IFAS Extension recommends filtering out particles down to about one-quarter the size of an emitter's smallest passage, so grouped or bridging particles don't cause clogging.
Manufacturer emitter, tubing and filter specifications always take priority over these general figures. For related data, see the soil infiltration rate chart and the PVC friction loss chart.
Related calculator categories
- Sprinkler calculatorsPrecipitation rates, zones, spacing and audits
- Irrigation hydraulics calculatorsPipe sizing, friction loss and available pressure
- Agriculture calculatorsField, orchard, vineyard and greenhouse irrigation math
- Garden and tree calculatorsBeds, vegetables, containers, trees and shrubs
- Soil calculatorsWater holding capacity and infiltration
- 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.
- Taghvaeian, S. Oklahoma Cooperative Extension Service. Drip Irrigation Systems (BAE-1511).
- University of Florida IFAS Extension. Screen Filters in Drip Irrigation Systems.