Spray tank mix calculator
Enter the tank, how much finished spray you put down per area, and the rate from the product label. The calculator gives the area that tank covers, the product to add and the water to make it up, for a full tank or for the space left above what is already in it. US gallons and litres both work.
The figures already in the form are an example, not a recommendation for any product. Use your own tank and the rates on your own labels; the label is the law, this page is arithmetic.
How the arithmetic works
Four steps, the same ones you would do on paper:
- Mix to make is the tank size, less what is already in it.
- Area it covers is that mix divided by your spray volume. One acre is 43,560 sq ft.
- Product is the label rate times that area. A rate for the active ingredient is divided by the product's concentration.
- Water is the mix less the product's own volume. A dry product is counted as adding no volume, so check its label for how to dissolve it.
Units are exact: one US gallon is 3.785411784 litres or 128 US fluid ounces, and one pound is 453.59237 grams. Imperial gallons are not used.
Worked examples (invented round numbers, not real labels)
A full tank, a liquid product. A 200 gal tank, empty. Spray volume 1 gal per 1,000 sq ft, so the tank covers 200,000 sq ft (4.59 acres). At 1.5 fl oz per 1,000 sq ft that is 300 fl oz of product, which is 2.34 gal or 8.87 L. Water: 200 − 2.34 = 197.66 gal (748.2 L).
A top-up, a dry product. A 300 gal tank still holding 120 gal, so 180 gal to mix. Spray volume 2 gal per 1,000 sq ft covers 90,000 sq ft, which is 2.07 acres. At 1 lb per acre that is 2.07 lb (937 g) of product, and 180 gal of water.
Litres and an active-ingredient rate. A 1,000 L tank (264.2 gal), empty. Spray volume 20 gal per acre covers 13.21 acres. A rate of 0.5 lb of active ingredient per acre from a product at 25 % is 2 lb of product per acre, so 26.42 lb (11.98 kg) for the tank.
Doing this every day, for every truck
Tank Tracker does this arithmetic at the fill dock for each truck, from your own mix rates, records what went in and what it cost, and keeps the record by truck. Try it with sample data: an eight-truck fleet with a season of fills, no login. Or start your own workspace. The help centre shows how the fill screen works.