Why use this calculator
Accurate spray dilution prevents costly errors in chemical application. Under-dosing wastes time and product with poor results, while over-dosing risks crop damage, environmental contamination, and regulatory non-compliance. This calculator ensures you mix the right amount of product for each tank fill.
How to use it
Enter the product application rate from the label (in ml per hectare), your spray tank capacity in litres, the water application rate in litres per hectare, and the total area to be sprayed. The calculator determines how much product to add per tank fill and the total product required.
The formula
Area Per Tank = Tank Size / Spray Rate. Product Per Tank = Product Rate x Area Per Tank. Tanks Needed = Field Area / Area Per Tank. Total Product = Product Rate x Field Area.
Worked examples
500 ml/ha product rate, 500L tank, 100 L/ha spray rate, 20 hectares
2,500 ml per tank fill, 4 tank fills, 10,000 ml total product
200 ml/ha product rate, 1000L tank, 200 L/ha spray rate, 50 hectares
1,000 ml per tank fill, 10 tank fills, 10,000 ml total product
When people use it
- Calculating chemical quantities for each tank mix
- Planning total product purchases for the spraying program
- Verifying correct mixing rates before application
- Training operators on proper chemical handling procedures
Tips
- Always read the product label for specific mixing instructions and compatibility warnings
- Measure product carefully using calibrated measuring equipment
- Add product to a partly-filled tank and agitate before topping up to final volume
- Record all application details including rates, conditions, and tank mixes for compliance
Questions people ask
- What spray rate should I use?
- Spray rates (water volume per hectare) depend on the product type, target pest/weed, and crop canopy density. Common rates range from 50-100 L/ha for broadacre cropping to 200-1000 L/ha for horticultural crops. Always follow label recommendations.
- Can I mix multiple products in one tank?
- Many products can be tank-mixed, but always check compatibility charts and label instructions. Add products in the correct order (typically wettable powders first, then liquid concentrates, then adjuvants). Conduct a jar test before mixing large volumes.