How do I calculate how much pesticide to put in my tank?

Divide the tank size by the spray volume to get the area one tank covers, then multiply by the label rate. A 300-gallon tank at 20 gallons per acre covers 15 acres; at 16 fl oz per acre that is 15 × 16 = 240 fl oz (1.875 gallons) of product per full tank, or 0.8 fl oz per gallon of spray.

How do I calibrate a sprayer?

Measure one nozzle's output in ounces per minute (divide by 128 for gallons per minute), time your speed over a measured course (mph = feet ÷ seconds × 0.682), and use GPA = 5940 × GPM ÷ (MPH × nozzle spacing in inches). At 0.3 GPM, 5 mph and 20-inch spacing the sprayer applies 17.8 gallons per acre. Check every nozzle; replace any that differ from the average by more than about 5–10%.

What is the 1/128 acre method?

Drive a course of 4,084 ÷ nozzle spacing (inches) feet, which is 1/128 acre per nozzle (for 20-inch spacing, 204 ft). Note the time, then catch one nozzle's spray for that same time while parked at the same pressure. Because a gallon is 128 fl oz, the ounces caught equal the gallons per acre.

How do I convert a rate per 1,000 sq ft to per acre?

Multiply by 43.56, since an acre is 43,560 sq ft. A turf label rate of 1 fl oz per 1,000 sq ft is 43.56 fl oz per acre; 2 gallons of water per 1,000 sq ft is 87.1 gallons per acre. Choose "per 1,000 sq ft" in the calculator to enter label rates directly.

How do I convert pounds of active ingredient to product?

For a liquid, divide by the pounds of active ingredient per gallon on the label: 1 lb a.i./acre of a 4 lb/gal concentrate is 0.25 gal = 32 fl oz per acre. For a dry product, divide by the fraction of active ingredient: 1 lb a.i. of an 80% wettable powder is 1.25 lb of product.

In what order should I mix products in the tank?

Follow the label first. The usual extension order is W-A-L-E-S: fill the tank half to three-quarters with water, add Wettable powders and water-dispersible granules, Agitate, then Liquid flowables and suspensions, Emulsifiable concentrates, and finally Solutions and Surfactants, then top up with water while agitating. Do a jar test when combining products for the first time.

What if the label gives a range such as 8–16 fl oz per acre?

Run the calculator at both ends. Labels usually reserve the higher rate for heavier pest pressure, larger weeds or longer residual. Never exceed the maximum single or seasonal rate on the label.

Pesticide Mix Calculator

Product per tank = label rate × tank size ÷ spray volume. At 16 fl oz/acre and 20 gal/acre, a 300-gal tank takes 240 fl oz and covers 15 acres. Calibrate first: GPA = 5940 × GPM ÷ (MPH × nozzle spacing in inches). Always follow the label.

Mixing Parameters

Label rate is given

Label rate (product per acre)

From the label. Use the rate for your crop, site and pest.

Spray volume (gallons per acre)

What your sprayer delivers: use the calibration panel below or a catch test.

Spray tank size (gallons)

Area to treat (optional)

Sprayer Calibration (GPA)

GPA = 5940 × GPM ÷ (MPH × W), W = nozzle spacing in inches (or swath width for a boomless nozzle).

Nozzle output

Speed (mph)

Spacing (in)

Speed check: feet

in seconds

Target GPA

Active Ingredient to Product

For recommendations written as lb a.i. per acre.

lb a.i. / acre

Formulation

lb a.i. per gallon (from the label)

Follow the label. It sets the legal maximum rate, the crops and sites, the mixing order, protective equipment and re-entry interval. This tool only does the arithmetic.

Fill in the parameters and click Calculate Mix Rate to see your results.

Tank mixing order (W-A-L-E-S)

0. WaterFill the tank ½ to ¾ with clean water and start agitation.
1. WWettable powders (WP) and water-dispersible granules (WDG, DF), pre-slurried if the label says so.
2. AAgitate until fully dispersed.
3. LLiquid flowables (F) and suspension concentrates (SC).
4. EEmulsifiable concentrates (EC).
5. SSolutions (SL) and surfactants or other adjuvants last, then top up with water.

If the label gives a different order, follow the label. Jar-test new combinations before filling the tank.

Summary

A pesticide label gives a rate of product per area, but you mix by the tank. The link is the spray volume your sprayer actually delivers: product per gallon = label rate ÷ spray volume, and product per tank = that × gallons in the tank. This calculator does the conversion for rates per acre or per 1,000 sq ft, in fl oz, mL, pints, quarts, gallons, ounces or pounds, totals the product and number of tanks for your area, calibrates the sprayer from nozzle output, speed and spacing, and turns an active-ingredient recommendation into a product rate. It does not choose a rate: the label is the legal limit for rate, crop, site, mixing order and protective equipment.

How it works

Choose whether the label rate is per acre or per 1,000 sq ft (turf and lawn labels often use 1,000 sq ft), then enter the rate and its unit.
Enter the spray volume in gallons per acre or per 1,000 sq ft. If you do not know it, calibrate: GPA = 5940 × nozzle flow (GPM) ÷ (speed in mph × nozzle spacing in inches), then press "Use this GPA".
Enter the tank size. Product per gallon = rate ÷ spray volume; product per tank = product per gallon × tank gallons; area per tank = tank gallons ÷ spray volume.
Add the area to treat for the total product and number of tank loads. 1 acre = 43,560 sq ft = 43.56 units of 1,000 sq ft.
If a recommendation is in pounds of active ingredient, convert it to a product rate first: product = lb a.i. ÷ (lb a.i. per gallon) for liquids, or lb a.i. ÷ (% a.i. ÷ 100) for dry products.

Use cases

Mix a 300-gallon boom sprayer for a 16 fl oz/acre herbicide at 20 GPA.
Fill a 2-gallon backpack sprayer for a lawn product labeled per 1,000 sq ft.
Calibrate a boom with 20-inch nozzle spacing before spraying.
Turn "1 lb a.i./acre" into fluid ounces of a 4 lb/gal concentrate.
Work out how much product to buy and how many tank loads a field needs.

Frequently Asked Questions

Last updated: 2026-10-10 · Reviewed by Nham Vu

Pesticide Mix Calculator

Mixing Parameters

Sprayer Calibration (GPA)

Active Ingredient to Product

Product per Gallon of Spray

Product per Full Tank

Total for the Area

Formula Breakdown

Tank mixing order (W-A-L-E-S)

Summary

How it works

Use cases

Frequently Asked Questions

Pesticide Mix Calculator

Use the Pesticide Mix Calculator

Mixing Parameters

Sprayer Calibration (GPA)

Active Ingredient to Product

Product per Gallon of Spray

Product per Full Tank

Total for the Area

Formula Breakdown

Tank mixing order (W-A-L-E-S)

Summary

How it works

Use cases

Frequently Asked Questions