The psi to gpm calculator works out cross sectional area of the pipe and flow rate in gpm from diameter of the pipe, pressure at the exit and pressure inside the tank. Enter what you have and the relationship is applied straight away, so you get the answer without working through the algebra yourself.
What Is the PSI to GPM Calculator?
The psi to gpm calculator converts diameter of the pipe, pressure at the exit and pressure inside the tank between the units you need, so you do not have to hunt for a factor and work it out longhand.
Conversion factors are where unit mistakes happen, and a mistake here tends to propagate silently into everything calculated from it afterwards.
How the PSI to GPM Conversion Works
Each conversion uses the exact factor defined for the unit, so the answer is right to the precision you would normally quote.
Convert at one end rather than at several. Converting to a common unit first and then back again introduces rounding that you then have to carry through the rest of the calculation.
Getting the Units Right
Check that the unit you are converting from is the unit you actually measured in. Similar-looking units, particularly gallons and litres or ounces and grams, are the usual source of a factor-of-ten error.
Write down both the value and its unit. A number without a unit is not a measurement, it is a guess.
A Worked Example
Working through an example, with diameter of the pipe set to 10, pressure at the exit set to 5, pressure inside the tank set to 2, the calculator returns cross sectional area of the pipe of 78.53982, and flow rate in gpm of -. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out cross sectional area of the pipe?
Enter diameter of the pipe, pressure at the exit and pressure inside the tank. The calculator then works through the relationship and reports cross sectional area of the pipe and flow rate in gpm.
What does the psi to gpm actually calculate?
It takes diameter of the pipe, pressure at the exit and pressure inside the tank and converts them into cross sectional area of the pipe and flow rate in gpm using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter diameter of the pipe?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Can I use this for a quick estimate as well as a precise answer?
Yes. The calculator is built for quick checks, so round your inputs to a sensible number of significant figures and the result will be just as useful. If you need more precision, keep the same method and add digits to the inputs rather than adjusting the method itself.
Is the answer exact?
It is as exact as the formula and the inputs allow. The method itself is the standard one for this problem, so the only sources of error are the figures you enter and the precision you ask for.