Calculators

Sprayer Calibration

Calibrate Before You Spray

Find out how many gallons your sprayer puts on an acre

Knowing your gallons per acre lets you mix the herbicide to match the label rate.

Step 1. Spray a measured area
Fill your sprayer with clean water. Never add herbicide for calibration. Measure out an area, spray it the way you normally would, and time how long it takes in seconds. Write the time down.
Area you sprayed
10 feet by 10 feet is 100 square feet. Change this if you measured a different area.
sq ft
Step 2. Catch the spray
Spray into a container for the same amount of time it took in step 1. Measure what you caught.
Amount caught
ounces
Step 3. Mix for your tank
Tank size
gallons
Product rate per acre (optional)
From the herbicide label. Use the label units, such as fluid ounces or pints.
Step 4. Notes
Notes
Add a name or sprayer unit number. It prints with your results.

The Math

Hand or backpack sprayer

Gallons caught = ounces caught ÷ 128

Gallons per acre = gallons caught × 43,560 ÷ square feet sprayed

Boom or boomless sprayer

Gallons per acre = total gallons per minute × 495 ÷ (miles per hour × swath width in feet)

Both

Acres per tank = tank size in gallons ÷ gallons per acre

Product per tank = label rate per acre × acres per tank

Questions About Rates?