How do you calculate sprayer gallons per acre?

Multiply the nozzle output in gallons per minute by 5940 and divide by the ground speed in mph times the nozzle spacing in inches. 0.25 GPM at 6 mph on 20 inch spacing is 0.25 × 5940 ÷ 120 = 12.38 gal/acre, the Sprayer Calibration calculator's own example.

Where does the 5940 come from?

It converts the units: 43,560 square feet in an acre, 60 minutes in an hour, 5,280 feet in a mile and 12 inches in a foot combine to 5940 when output is in GPM, speed in mph and spacing in inches.

How do I hit the target rate?

The Speed for target column gives the ground speed that applies the target at the measured output: output × 5940 ÷ (target × spacing). Small corrections are best made with speed or a modest pressure change; larger ones need different tips.

When should nozzle tips be replaced?

When a nozzle puts out noticeably more than a new tip at the same pressure. The workbook compares the highest nozzle in the catch test with the tip's rated output at the pressure used and flags Replace tips when it is above the wear limit on Setup (10% in the example).

How does pressure change nozzle output?

Output varies with the square root of the pressure. A tip rated 0.50 GPM at 40 psi gives 0.50 × √(35 ÷ 40) = 0.47 GPM at 35 psi; doubling the output takes four times the pressure.

Does the workbook use macros?

No. It is a plain .xlsx with ordinary formulas, tables and native charts. The Verify sheet re-checks the formulas against fixed test checks and shows Self-check: PASS.

Quality and Inspection

Sprayer Calibration Log Excel Template

Gallons per acre = nozzle GPM × 5940 ÷ (ground speed mph × nozzle spacing in inches). Log every catch test on your boom sprayers and see the applied rate against the target, the ground speed that would hit it, and how worn the tips are against their rated output at the pressure you spray at.

Free, and a plain .xlsx with no macros to enable. A CSV with live formulas and a printed how-to guide come with it.

Overview

This sprayer calibration log is a working Excel workbook for farm managers, spray operators, agronomists and contract sprayers. Each calibration check is one row with its sprayer, tip, boom pressure, the ground speed measured over a timed course, the average and highest nozzle output from the catch test, and the target rate; each sprayer's nozzle spacing, nozzles and tank and each tip's rated output come from Setup. The workbook gives the applied rate in gallons per acre and its error against the target, the ground speed that would hit the target, the tips' rated output at the pressure and how far the worst nozzle is above it, and the acres a tank covers. It ships with a season of 16 checks on five sprayers at a fictional farm, so every tile and chart is filled in when you open it.

In the example the 60 ft boom puts out 0.41 GPM a nozzle at 8 mph on 20 inch spacing: 15.22 gal/acre, 1.5% over a 15 gallon target. By August its worst nozzle is 13.8% above the tips' rated 0.40 GPM and the rate is 6.4% high, so the tips are replaced. The 90 ft boom's old tips were 14% worn in April although its average rate was still within 5%. The ATV sprayer under-applied by 19.6% when a new operator drove it at 4.8 mph instead of 4.

Calibrate with clean water at spraying pressure and re-check after changing tips, pressure or speed; a catch test does not check the spray pattern. The download is a plain .xlsx with no macros. A CSV with live formulas is also included for other tools; the dashboard, charts, dropdowns and self-check are in the .xlsx.

What this template includes

Setup sheet with your operation, rate tolerance and tip wear limit, the sprayers with their nozzle spacing, nozzles and tank, and the tips with their rated output and pressure
Checks table, one row per calibration: date, sprayer, tip, pressure, ground speed, average and highest nozzle output from the catch test, and target rate, with a Check column
Per check: speed × spacing, applied rate, rate error, a status in words, speed for the target, rated tip output at the pressure, tip wear, replace tips (Yes/No), boom output and acres per tank
Dashboard with four tiles (checks, out of tolerance, tips to replace, largest rate error), rate error and tip wear at the last four checks of the sprayer you pick, applied rate against target at each sprayer's latest check, and the sprayer and trend tables
Method sheet with every formula, and a Verify sheet that re-checks the formulas against an independent reference and the Sprayer Calibration calculator (Self-check: PASS)
CSV with live formulas for the Checks table; the dashboard, charts, dropdowns and self-check are in the .xlsx

Suggested use case

Use it to keep a calibration record for every sprayer through the season, to set the ground speed that gives the label rate, or to know when worn tips need replacing before they throw the rate out.

How to use it

On Setup, set your rate tolerance and tip wear limit, and list your sprayers with their nozzle spacing, nozzles and tank, and your tips with their rated output and pressure.
On Checks, give each calibration a row: date, sprayer, tip, pressure, ground speed, the average and highest nozzle output from the catch test, and the target rate.
Fix anything the Check column names.
Open the Dashboard: pick a sprayer for its season trend, and see every sprayer's rate against target at its latest check.

Frequently Asked Questions

How do you calculate sprayer gallons per acre?: Multiply the nozzle output in gallons per minute by 5940 and divide by the ground speed in mph times the nozzle spacing in inches. 0.25 GPM at 6 mph on 20 inch spacing is 0.25 × 5940 ÷ 120 = 12.38 gal/acre, the Sprayer Calibration calculator's own example.
Where does the 5940 come from?: It converts the units: 43,560 square feet in an acre, 60 minutes in an hour, 5,280 feet in a mile and 12 inches in a foot combine to 5940 when output is in GPM, speed in mph and spacing in inches.
How do I hit the target rate?: The Speed for target column gives the ground speed that applies the target at the measured output: output × 5940 ÷ (target × spacing). Small corrections are best made with speed or a modest pressure change; larger ones need different tips.
When should nozzle tips be replaced?: When a nozzle puts out noticeably more than a new tip at the same pressure. The workbook compares the highest nozzle in the catch test with the tip's rated output at the pressure used and flags Replace tips when it is above the wear limit on Setup (10% in the example).
How does pressure change nozzle output?: Output varies with the square root of the pressure. A tip rated 0.50 GPM at 40 psi gives 0.50 × √(35 ÷ 40) = 0.47 GPM at 35 psi; doubling the output takes four times the pressure.
Does the workbook use macros?: No. It is a plain .xlsx with ordinary formulas, tables and native charts. The Verify sheet re-checks the formulas against fixed test checks and shows Self-check: PASS.