Interactive Worksheet G1270 — New July 13, 1999

Nozzle Flow Rate Calculator

William W. Casady and H. Willard Downs, Department of Agricultural Engineering
Fred Fishel, Department of Agronomy

This worksheet is for educational purposes. The University of Missouri is not responsible for any actions taken as a result of using this worksheet.


1. Sprayer application rate gallons/acre
2. Field speed mph
3. Width sprayed by each nozzle inches
4. Nozzle flow rate
= ( line 1 x line 2 x line 3 ) ÷ 5,940
0.00 gallons per minute
0.00 oz. per minute

Worksheet definitions:

  1. Sprayer application rate — A recommended range of sprayer application rates, in gallons per acre, is given on the pesticide label. From that range, choose the rate that is compatible with your spraying equipment.
  2. Field speed — Choose a speed that can be maintained at all times. A 10 percent reduction in speed will result in a similar overapplication of pesticides. Where speed must be reduced for a short period at the end of a pass through the field or in other situations, a small reduction in engine speed is preferable to selecting a lower gear. Reducing the engine speed causes the nozzle flow rate as well as the travel speed to decrease, although not proportionately. If slowing is frequently necessary, calibrate the sprayer for the slower speed.
  3. Width sprayed by each nozzle — The width sprayed by each nozzle on a broadcast spray boom is the distance between nozzles. If a sprayer has nozzles spaced every 20 inches on the boom, the width sprayed by each nozzle is 20 inches. If a sprayer has several nozzles that will be used to spray each row, such as sprayers used to apply insecticides to row crops, then the width sprayed by each nozzle is the distance between rows divided by the number of nozzles used to spray each row. If the sprayer is a band sprayer and the labeled rate applies to the actual area sprayed, the width is the width of the band. If the sprayer is a band sprayer and the labeled rate applies to the total area covered, the width is the spacing between rows.

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Copyright 1999 University of Missouri. Published by University Extension, University of Missouri-Columbia.

Issued in furtherance of Cooperative Extension Work Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. Ronald J. Turner, Director, Cooperative Extension Service, University of Missouri and Lincoln University, Columbia, Missouri 65211. • University Extension does not discriminate on the basis of race, color, national origin, sex, religion, age, disability or status as a Vietnam era veteran in employment or programs. If you have special needs as addressed by the Americans with Disabilities Act and need this publication in an alternative format, write ADA Officer, Extension and Agricultural Information, 1-98 Agriculture Building, Columbia, MO 65211, or call (573) 882-8237. Reasonable efforts will be made to accommodate your special needs.