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Irrigation Flow, Runtime and Catch-Test Calculator

Calculate drip emitter delivery, measured emitter flow, sprinkler precipitation and sampled uniformity. Convert a chosen water amount into runtime.

Use this result well

Inputs that matter
Emitter volume unit, Number of emitters, Flow per emitter per hour, Run time (hours), and 6 more
Output to expect
Emitter flow and runtime, Emitter collection test, Sprinkler catch test
  • Check the units and required inputs before comparing results.
  • Keep the assumptions with a copied result so you can reproduce the calculation later.
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Reference & details

How it works

Nominal emitter delivery

Count and discharge must describe the same operating zone and pressure basis. US liquid gallons are converted with 3.785411784 liters per gallon.

Flow = count × emitter rate; volume = flow × hours

Timed collection

Emitter catches use mL per emitter. Sprinkler catches use depth in mm or inches. Each reading belongs to the same collection duration.

Mean rate = mean catch × 60 ÷ minutes

Sample uniformity

DUlq uses a whole lower quarter; the tool does not round sample count or rate the system as compliant. Values use numeric arithmetic, with small nonzero results shown in scientific notation when needed.

DUlq (%) = low-quarter mean ÷ overall mean × 100

Updated: September 2026

Example Scenarios

60 emitters at 0.5 US gal/hour for 1.5 hours.

→ 30 US gal/hour and 45 US gallons delivered.

80, 100, 100 and 120 mL collected over six minutes.

→ Mean 1 L/hour per sampled emitter; DUlq 80%.

4, 5, 5 and 6 mm over 20 minutes, with a chosen 10 mm target.

→ 15 mm/hour average; DUlq 80%; 40 minutes for the average target.

Common Mistakes to Avoid

Entering mL as sprinkler depth

Read depth in equal-opening catch cups for sprinkler mode; emitter mode expects collected milliliters.

Treating DUlq as application efficiency

DUlq measures sampled distribution. Soil infiltration, evaporation, runoff and other losses need separate evidence.

FAQ

Calculate each equal-rated group separately and add their flows in the zone record. The nominal flow mode assumes all counted emitters deliver the same entered rate.

A dry or blocked position is part of the observed distribution. Removing it can hide poor delivery. Invalid or missing entries must be corrected rather than treated as zero.

For 4, 8, 12…100 equally weighted samples, divide the average of the smallest quarter by the average of all readings. Other sample counts still produce mean rate, but no DUlq. All-zero readings have no defined DUlq.

No. It converts a chosen volume or average depth with the entered or measured rate. Sprinkler runtime is based on the sample mean; inspect uneven coverage and runoff separately.

About Irrigation Flow, Runtime and Catch-Test Calculator

Use one of three modes: nominal emitter flow, timed emitter collections, or sprinkler catch depths. Each result retains its unit and test basis. Save the calculation with raw readings and conditions; the tool does not choose equipment pressure, pipe size or a crop schedule.