Spray Mix Calculator
Calculate product per tank, total product and number of tank loads.
Please note: Planning figures based on published averages. Soil type, climate, variety, season and local practice all shift these results substantially. Base real decisions on a soil test, local extension guidance and the product label — particularly for fertiliser, lime and any crop protection product, where the label is a legal document.
What the Spray Mix Calculator does
Spray mixing works from two independent rates: how much product each hectare needs, and how much water carries it. The tank size divided by the water rate gives the area one load covers, and that area times the product rate gives what goes in the tank.
Formula
Area per tank = Tank size ÷ Water rateProduct per tank = Product rate × Area per tankTotal product = Product rate × AreaTank loads = ⌈Area ÷ Area per tank⌉
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Product rate | number | Yes | From the product label, per hectare. Accepts more than 0. |
| Rate measured in | one of 3 options | Yes | — |
| Water volume | litres/ha | Yes | Accepts more than 0. |
| Sprayer tank capacity | litres | Yes | Accepts 0 or more. |
| Area to spray | number | Yes | Accepts more than 0. |
| Area to spray unit | one of 4 options | Yes | — |
| Product price per litre or kg | selected currency | Optional | Accepts 0 or more. |
| Currency | one of 10 options | Optional | — |
How to use it
- Choose Rate measured in and Area to spray unit.
- Enter Product rate, Water volume, Sprayer tank capacity and Area to spray.
- Optionally add Product price per litre or kg.
- Select Calculate.
Worked example
A product at 2 L/ha, sprayed at 200 L/ha of water from a 500 litre tank over 20 hectares.
- Rate
- 2 L/ha
- Water
- 200 L/ha
- Tank
- 500 L
- Area
- 20 ha
Each tank covers 2.5 ha and takes 5 L of product. The job needs 40 L of product, 4,000 L of water and 8 tank loads.
Frequently asked questions
What if the last tank is only part full?
Mix only the product that partial area needs. The calculator shows the part-load area and its product and water so you avoid surplus.
Does changing the water rate change the product rate?
No. The product per hectare is fixed by the label. A different water volume only changes how concentrated the tank is and how many loads you need.