Independent: We are not a state agency and not affiliated with the EPA or any state department of agriculture. Always confirm requirements with your state department of agriculture. Rev. 2026.07.30
Applicator Prep Applicator License Calibrate your equipment

Home / Calibration / Boom sprayer

Equipment 2 of 4, free tool, your measurements stay on your device

Boom and broadcast sprayer calibration

Quotable answer

How do I calibrate a boom sprayer?

Catch one nozzle's output for exactly 60 seconds at field operating pressure, convert that catch to gallons per minute (divide ounces by 128), time your travel speed over a measured course, then combine gallons per minute, speed in miles per hour, and nozzle spacing in inches using gallons per acre equals gallons-per-minute times 5,940, divided by speed times spacing.

Backpack Boom Airblast Granular
Step 2, guided catch test

Run the per-nozzle catch test

Catch one nozzle's output over exactly one minute while the sprayer is stationary and running at operating pressure, then combine that flow with your travel speed and nozzle spacing using the standard boom calibration constant, 5,940 (it converts ounces per minute, miles per hour, and inches of spacing into gallons per acre).

Diagram of a boom sprayer catch test: a spray boom with several evenly spaced nozzles, one nozzle highlighted with its output streaming into a graduated collection jar timed with a stopwatch.
Catch one nozzle for exactly one minute, then combine with speed and spacing using the 5,940 constant.
  1. Measure the nozzle spacing on the boom, in inches, center to center.
  2. Drive a measured 100-foot or 200-foot course at your actual field ground speed and time it, to get miles per hour.
  3. With the sprayer stationary and at field operating pressure, catch one nozzle's output for exactly 60 seconds, in ounces.
  4. Convert the catch to gallons per minute (divide ounces by 128), then output rate (GPA) equals that gallons-per-minute figure times 5,940, divided by (speed in mph times nozzle spacing in inches).

gpm = oz/min / 128; GPA = (gpm x 5,940) / (mph x nozzle spacing in inches)

Step 3

Label-rate and mix-rate math

Enter the label's target rate exactly as it is printed, in whichever unit the label uses, and your tank size. The workflow converts to ounces of product per gallon of water and per full tank, with the unit conversion shown.

The pesticide label is the legal controlling document. This workflow is a study and field-planning aid, never a substitute for label directions. Learn more about how output rate is calculated or use the standalone mix-rate converter.

FAQ

Common questions

Frequently asked questions

Where does the 5,940 constant come from?
It is a unit-conversion constant that lets you combine ounces per minute, miles per hour, and inches of nozzle spacing directly into gallons per acre, without converting each measurement into a common unit system by hand first. It is standard across boom-sprayer calibration guidance nationally.
Why does nozzle spacing matter if I already know my total flow?
Total boom flow alone does not tell you the rate over the ground each nozzle actually covers. Spacing sets how much ground each nozzle is responsible for, so the same total flow applies a different gallons-per-acre rate on a boom with wide spacing than one with narrow spacing.
Do all nozzles need to be checked, or just one?
Check more than one. This workflow computes GPA from a single nozzle's catch, which assumes every nozzle on the boom is delivering the same output; a clogged or worn nozzle breaks that assumption, so a quick visual or catch check across the boom is worth the extra minute before you trust one nozzle's number for the whole pass.