Pesticide Mixing Calculator
Determine how much pesticide concentrate to add to your spray tank for a given field area, application rate, and tank size. Use it every time you prepare a tank mix to avoid under- or over-dosing.
Last updated: September 2026
Formula below · 2 sources (usda.gov, Wikipedia) · Updated Sep 2026
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About this calculator
Correct pesticide mixing matches the product added to each tank to the area that tank will cover. One full tank covers tankSize ÷ waterRate acres, so each full tank needs applicationRate × (tankSize ÷ waterRate) ounces of active ingredient; dividing by the concentration converts active ingredient into ounces of the commercial product. If the whole job needs less than one tank (sprayArea × waterRate is smaller than the tank), only that volume is mixed. The formula is: Product per Tank (oz) = applicationRate ÷ concentration × min(tankSize, sprayArea × waterRate) ÷ waterRate. Enter the application rate as ounces of active ingredient per acre; if your label already gives the rate as ounces of product per acre, choose 100% Active Ingredient so no conversion is applied. The number of tank loads is sprayArea × waterRate ÷ tankSize, and the total product for the job is sprayArea × applicationRate ÷ concentration. Always calibrate your sprayer nozzles before mixing to ensure the water application rate is accurate.
How to use
You need to spray 10 acres at 8 oz/acre (product rate, so choose 100% Active Ingredient), with a 100-gallon tank and a water rate of 20 gal/acre. Step 1 — Acres per tank: 100 / 20 = 5 acres. Step 2 — Product per tank: 8 oz/acre × 5 acres = 40 oz. Step 3 — Tank loads: 10 × 20 / 100 = 2 full tanks, so the job uses 80 oz in total. Using the formula: 8 / 1 × min(100, 10 × 20) / 20 = 8 × 100 / 20 = 40 oz per tank load. With a 50% active-ingredient product and a rate given as active ingredient, the same job needs 80 oz of product per tank.
Frequently asked questions
How do I calculate how much pesticide to add per tank load for my sprayer?
Divide the total pesticide needed for the entire job by the number of tank loads required. Total pesticide (oz) equals the area in acres multiplied by the labeled application rate in oz/acre. Tank loads equals total water volume (area × water rate per acre) divided by tank capacity. Keeping these calculations separate before combining them reduces mixing errors. Always double-check your math against the pesticide label, which is a legal document specifying minimum and maximum rates.
What is the water application rate and why does it matter for pesticide mixing?
The water application rate, measured in gallons per acre, is how much spray solution your equipment deposits on each acre of crop. It affects droplet coverage, canopy penetration, and drift risk. Typical field sprayers run 10–20 gal/acre, while orchard airblast sprayers may use 50–100 gal/acre. The water rate determines how many tank loads you need per field, which directly sets how much concentrate goes into each individual tank. If your actual water rate differs from your assumed rate — due to nozzle wear or speed changes — your pesticide dose per acre will be off.
Why is it important to calibrate a sprayer before mixing pesticides?
Calibration verifies that your sprayer delivers the intended volume of water per acre at your operating speed and pressure. Even brand-new nozzles can vary ±5–10% from their rated output, and worn nozzles may deliver 20% or more above the rated rate. An uncalibrated sprayer means your calculated mix ratio produces the wrong field dose — potentially causing crop damage from overdosing or pest survival from underdosing, both of which carry regulatory and economic consequences. Calibrate at the start of each season and whenever nozzles are replaced.
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