Sprayer Calibration Calculator: ISO Nozzle Flow Rate

Sprayer calibration: nozzle flow rate, pressure and ISO colour

The flow each nozzle must deliver is q (L/min) = volume per ha × speed (km/h) × spacing (m) ÷ 600. At 120 L/ha, 8.5 km/h and 50 cm spacing, each nozzle needs 0.85 L/min: the tool picks a yellow ISO 02 nozzle at 3.39 bar, which fills 1 litre in 70.6 seconds in the jug test.

The formulas

• Flow per nozzle: q = V × v × s ÷ 600 (V in L/ha, v in km/h, s in m).
• Number of nozzles = boom width ÷ spacing; boom output = q × number of nozzles.
• Pressure for a given nozzle: P = 3 × (q ÷ rated flow at 3 bar)². The tool tests ISO sizes from 01 (orange, 0.4 L/min at 3 bar) to 08 (white, 3.2 L/min) and keeps the one whose pressure, between 1.5 and 5 bar, is closest to 2.8 bar.
• Jug test: time for 1 litre = 60 ÷ q seconds.
• Area per tank = capacity ÷ volume per ha; work rate = width × speed ÷ 10 (ha/h).

Worked example

120 L/ha, 8.5 km/h, nozzles at 50 cm, 24 m boom, 3,000 L tank, 45 ha: q = 120 × 8.5 × 0.5 ÷ 600 = 0.85 L/min, 48 nozzles, 40.8 L/min for the boom. Yellow 02 nozzle: 3 × (0.85 ÷ 0.8)² = 3.39 bar (lilac 025 would need 2.17 bar, slightly further from 2.8). Jug test: 1 litre in 70.6 s. One tank covers 25 ha, so 1.8 tanks for 45 ha, at 20.4 ha/h.

Limits

The square-root pressure-flow relation is an approximation that suits standard flat-fan nozzles; air-induction nozzles have their own manufacturer charts. Real ground speed, measured in the field, takes precedence over the speedometer. The tool gives no product rate: it sets the spray volume only. In France, sprayers must still pass a periodic inspection every 3 years.

Sources and dates: colour codes and rated flows at 3 bar: standard ISO 10625, not consulted online; 3-year validity of the inspection and first inspection of new equipment within 5 years: French Rural and Maritime Fishing Code, art. D256-13, version in force since 01/10/2021 (checked 14/10/2026).

Frequently Asked Questions

What is the formula for sprayer nozzle flow rate?

Flow (L/min) = volume per ha × speed (km/h) × nozzle spacing (m) ÷ 600. For 120 L/ha at 8.5 km/h with nozzles every 50 cm, each nozzle must deliver 0.85 L/min.

Which ISO nozzle colour should I choose?

Each colour matches a flow at 3 bar: orange 01 = 0.4 L/min, green 015 = 0.6, yellow 02 = 0.8, lilac 025 = 1.0, blue 03 = 1.2, red 04 = 1.6 L/min. The tool keeps the size that reaches the target flow at a pressure close to 2.8 bar, between 1.5 and 5 bar.

How do I check nozzle output with a measuring jug?

Time how long each nozzle takes to fill one litre: it should take 60 ÷ flow seconds, i.e. 70.6 s for 0.85 L/min. A nozzle clearly faster than the others is worn and should be replaced.

How often must a sprayer be inspected in France?

In France, an inspection is valid for 3 years from the inspection report, and new equipment must be inspected at least once within 5 years of purchase (Rural Code, art. D256-13, in force since 01/10/2021).

Is this tool really free?

Yes, all tools on Kristools are 100% free and accessible without registration.

Is my data protected?

Yes. All processing is performed directly and securely inside your browser. No personal data is sent to our servers.