Enter the flow rate through the nozzle (GPM) and the nozzle diameter (in) into the calculator to determine the Nozzle Pressure. 

Nozzle Pressure Formula

The following formula is used to calculate the Nozzle Pressure. 

Pnozzle = [FR/(29.71*D^2)]^2
  • Where Pnozzle is the Nozzle Pressure (psi)
  • FR is the flow rate through the nozzle (GPM) 
  • D is the nozzle diameter (in) 

To calculate the nozzle pressure, divide the flow rate by 29.71 times the diameter squared, then square this result.

How to Calculate Nozzle Pressure?

The following two example problems outline how to calculate the Nozzle Pressure.

Example Problem #1:

  1. First, determine the flow rate through the nozzle (GPM). In this example, the flow rate through the nozzle (GPM) is given as 50.
  2. Next, determine the nozzle diameter (in). For this problem, the nozzle diameter (in) is given as 2.
  3. Finally, calculate the Nozzle Pressure using the equation above: 

Pnozzle = [FR/(29.71*D^2)]^2

Inserting the values from above and solving the equation: 

Pnozzle = [50/(29.71*2^2)]^2 = .177 (psi)

Example Problem #2: 

Using the same process as above, first define the variables required by the formula. In this case, these values are:

flow rate through the nozzle (GPM) = 100

nozzle diameter (in) = .75

Entering these values yields:

Pnozzle = [100/(29.71*.75^2)]^2 = 35.805 (psi)