Spray Mix Calculators Nozzle Flow Rate Calculator

Nozzle Flow Rate Calculator

Calculate nozzle output from a quick catch test (measured volume over time), or compute the required nozzle flow from your target rate, speed, and nozzle spacing. Results include GPM, L/min, oz/min, and mL/min.

Jump to: Calculator · Common flow rates table · FAQ

Next step after flow? Calibrate your sprayer · Check area coverage: Spray Coverage Calculator · Pressure reference: PSI vs GPM · Ready to mix? Use the Spray Mix Calculator.

How to measure nozzle flow rate (catch test)

  1. Set pressure and clean filters: Use your intended pressure and make sure strainers/filters are clean.
  2. Catch one nozzle output: Catch spray from one nozzle for a timed interval (commonly 60 seconds).
  3. Measure the volume: Record the amount collected (fl oz or mL) and the time in seconds.
  4. Enter your measurement: Use “Measured output” mode to convert to GPM/L/min.
  5. Compare nozzles: Repeat for a few nozzles. Replace outliers to improve uniform coverage.

If you’re adjusting pressure and want an estimate of how flow changes, use PSI vs GPM Reference.

Calculator

Measure or Compute Nozzle Flow

Use Measured output (catch test) to get actual nozzle flow. Use Required flow to choose a nozzle size that matches a target application rate. Required flow estimates assume standard boom/broadcast spacing math.

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For best accuracy, test multiple nozzles. If one nozzle is noticeably different from the others, clean/replace it before spraying.

Quick tips (high-impact)

Common spray nozzle flow rates (reference)

Use this table to compare your catch test results against typical manufacturer specs. Flow rates vary by pressure — values below are at 40 PSI (a common operating pressure):

Nozzle Size GPM at 40 PSI L/min at 40 PSI Oz/min at 40 PSI
01 (0.1) 0.10 0.38 12.8
015 (0.15) 0.15 0.57 19.2
02 (0.2) 0.20 0.76 25.6
03 (0.3) 0.30 1.14 38.4
04 (0.4) 0.40 1.51 51.2
05 (0.5) 0.50 1.89 64.0
06 (0.6) 0.60 2.27 76.8
08 (0.8) 0.80 3.03 102.4
10 (1.0) 1.00 3.79 128.0

Nozzle size numbers refer to GPM at 40 PSI (e.g., an "03" nozzle flows 0.3 GPM at 40 PSI). Actual flow varies with pressure — see the PSI vs GPM Reference for adjustments.

How pressure affects nozzle flow rate

Flow rate changes with the square root of pressure. Doubling pressure does not double flow — it increases flow by about 41%. To double flow, you need to quadruple pressure. In practice, most sprayers operate between 20–60 PSI:

For exact flow at any pressure, use the PSI vs GPM Reference Calculator.

Recommended gear (optional)

This page is easiest when you can measure accurately and keep pressure stable. Many users keep a small kit:

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FAQ

How do I convert ounces per minute to GPM?

Divide oz/min by 128 to get GPM (since 128 fl oz = 1 gallon). Example: 25.6 oz/min = 0.20 GPM.

How do I convert mL per minute to L/min?

Divide mL/min by 1000 to get L/min. Example: 450 mL/min = 0.45 L/min.

How do I calculate required nozzle flow from GPA?

A common boom formula is: GPM per nozzle = (GPA × MPH × spacing in inches) ÷ 5940. Use the “Required nozzle flow” mode and the calculator will compute it.

Why do my nozzles have different flow rates?

Wear, clogs, damaged strainers, or inconsistent pressure can cause differences. Measuring and replacing outliers helps ensure even coverage and avoids over/under application.