What is carrier volume and where do I find it?

Carrier volume is the amount of water applied per hectare (L/ha). It's typically set by your boom sprayer calibration, not the chemical label. Standard boom spray rates are 80–100 L/ha.

What if I'm not sure how many litres my tank holds?

Calibrate your tank with a flow meter or by filling it from measured containers. Tank capacity marked on the sprayer may not be accurate if the sprayer has been modified.

Can I mix herbicide and fertiliser in the same tank?

Sometimes — but always check the specific products for compatibility. Foliar nitrogen (UAN) can be tank-mixed with some herbicides. Check the label and conduct a jar test before committing to a full load.

Spray Rate / Chemical Dilution — Free Agriculture Calculator

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Tank's on the boom and the chemical's in the shed. The label says L/ha but you need to know exactly how much product goes in the tank to cover your paddock.

Spray Rate / Chemical Dilution

Spraying

Mode

Tank size (L)

Imperial: enter gallons

Application rate (L/ha)

From label — e.g. 1.5 L/ha

Area to cover per tank (ha)

Chemical per tank = Rate (L/ha) × Area covered (ha) Area per tank = Tank size (L) ÷ Carrier volume (L/ha) Mixing order: Fill tank to 50% with water → add chemical → top up with water → agitate.
Always read the label. Wear PPE. Check withholding periods and re-entry intervals.

Reference: APVMA — Australian Pesticides & Veterinary Medicines Authority · GRDC Spray Application Manual

ℹ️ Results are estimates for planning purposes. Verify with current standards and a qualified professional.

1 What this calculator does

Calculates chemical product volume per tank fill from your application rate (L/ha or fl.oz/acre), paddock area, tank volume and water carrier volume. Shows how many tank loads needed to cover the paddock and product required for the whole job.

2 Formula & professional reasoning

Product per tank (L) = Application rate (L/ha) × [Tank volume (L) ÷ Carrier volume (L/ha)]

The carrier volume (L/ha) is the total water applied per hectare. Dividing tank volume by carrier volume gives you the area per tank. Multiplying that area by the product rate gives you how much chemical to add per tank. This ensures constant product concentration regardless of tank size.

3 Worked examples

⚠️ Illustrative example only — not clinical or professional instruction.

Basic

Simple herbicide application

Given: Rate: 1.5 L/ha · Tank: 2000 L · Carrier: 100 L/ha · Area: 200 ha

Working: Area/tank: 2000÷100=20 ha · Product/tank: 1.5×20=30 L

Answer: 30 L product per 2000 L tank

💡 Total tanks: 200÷20=10 loads. Total product: 1.5×200=300 L.

Standard

Fungicide with multiple active ingredients

Given: Rate: 250 mL/ha · Tank: 3000 L · Carrier: 80 L/ha · Area: 450 ha

Working: 3000÷80=37.5 ha/tank · 0.25×37.5=9.375 L

Answer: 9.4 L (9375 mL) per 3000 L tank

💡 12 full tanks to cover 450 ha. Order 113 L total.

Advanced

Imperial: oz/ac on 500-gallon sprayer

Given: Rate: 32 fl oz/ac · Carrier: 15 gal/ac · Tank: 500 gal · Area: 320 ac

Working: 500÷15=33.3 ac/tank · 32×33.3=1067 fl oz (8.3 gal)

Answer: 8.3 gallons product per 500-gal tank

💡 10 tanks for 320 acres. Total product: 32×320=10,240 fl oz = 80 gallons.

4 Sanity check

Label rate must be followed

Exceeding rate is illegal

Underdosing reduces efficacy. Overdosing is an environmental offence.

Carrier volume range

50–200 L/ha typical boom spray

Low-volume: 50–80 L/ha. Standard: 80–120 L/ha. High-volume: 120–200 L/ha.

Tank mix compatibility

Check label before mixing products

Some herbicides and fungicides cannot be tank-mixed — always check compatibility charts.

Re-entry and withholding

Check label before treatment

Withholding period applies from date of last application to harvest.

5 Common errors

Error	Cause	Consequence	Fix
Rate in L/ha but carrier in L/100 L	Unit confusion on label	10× concentration error	Convert L/100 L to L/ha by multiplying by carrier volume ÷ 100
Not accounting for half-tanks at end	Assuming all tanks are full	Last load over-concentrated	Fill final tank to the correct volume and adjust product proportionally
Mixing sequence ignored	Adding products in wrong order	Precipitation, reduced efficacy	ALWAYS follow mixing order: water first, then wettable powders, then emulsifiable concentrates, then other liquids
No calibration check	Assuming sprayer flow rate is correct	Actual L/ha differs from design	Calibrate sprayer at the start of every season and after any nozzle change