Example with over-application
Input Speed 6.0km/h, nozzle spacing 50cm × 24 = width 12.0m, total flow 14.8L/min, target 100L/ha
Output Current 123L/ha, deviation +23%, recommended 7.4km/h or 12.0L/min (0.50L/min per nozzle)
Spray Application Rate Calculator (Simple Sprayer Calibration)
Calculate current spray rate in L/ha and gal/acre from travel speed, spray width, and flow.
See the gap from your target rate and the exact adjustment to make by speed or by flow.
Get spray rate from just three required inputs
See whether speed or flow should be changed
Unit switching, shareable links, and saved last values
Important safety notes
Always follow the product label, SDS, and sprayer manufacturer instructions.
This tool is for simple application-rate calibration. Measure speed, width, and flow in the field.
Pressure-based adjustment is reference only. Re-measure actual flow after any change.
How to use
- Choose the unit system and enter travel speed, spray width, and flow.
- Use the helper fields if you want to estimate speed from distance and time or width from nozzle spacing and count.
- Check the current spray rate, then enter a target rate to see the deviation and adjustment guidance.
- Copy the result or copy a shareable link for field use.
Sample
Field measurement steps
- Drive a fixed distance at steady throttle and calculate speed from the elapsed time.
- Use actual spray width, not only the full boom width.
- Measure one-minute output under normal working conditions and enter either the total flow or an average per nozzle.
Formulas and units
- L/ha = (600 × flow[L/min]) ÷ (speed[km/h] × width[m])
- gal/acre = (495 × flow[gal/min]) ÷ (speed[mph] × width[ft])
- Required speed = current speed × (current rate ÷ target rate)
- Required flow = current flow × (target rate ÷ current rate)
- Required pressure ≈ current pressure × (required flow ÷ current flow)^2
- Measured speed: km/h = distance[m] ÷ time[s] × 3.6
FAQ
My units are mixed.
You can switch between km/h and mph, m and ft, L/min and gal/min, and L/ha and gal/acre at any time. Values are converted automatically.
I have multiple nozzles.
Choose per-nozzle flow × count to calculate total flow automatically. If nozzle output varies, measure several nozzles and enter the average.
Can I calculate flow from pressure?
This tool recommends measured flow as the main input. Pressure-based conversion is shown only as a reference because nozzle wear and field conditions can change actual output.
Notes
- This is a simple calibration tool and assumes field measurements for speed, width, and flow.
- Spray rate changes with nozzle wear, liquid viscosity, filter clogging, pressure fluctuation, terrain, and wheel slip.
- Set the target rate according to the label and official instructions for the crop, product, and dilution plan.