PSI to GPM Calculator

Your details

Choose the direction of the conversion.
Use Hazen-Williams for long pipe runs. Use the orifice method for nozzles, sprinkler heads, hydrant outlets, or short openings.
Water pressure at the inlet of the pipe, in pounds per square inch.
PSI
Inside diameter of the pipe or orifice opening.
The Hazen-Williams C coefficient describes pipe roughness. Smoother pipes (higher C) carry more flow at the same pressure.
Total length of the pipe run in feet.
ft
Pressure at the end of the pipe. Use 0 for free discharge (open air). For a pressurised downstream system, enter that backpressure here.
PSI
Pressure reading at the orifice inlet or from a pitot gauge, in PSI.
PSI
Flow rateFlow velocity too high (erosion risk)
50.32GPM

Gallons per minute of water flowing through the pipe or orifice.

Pressure used / drop60PSI
Water velocity20.55ft/s
Flow rate (GPH)3,019GPH
Hazen-Williams C150
20.55 ft/s
Too slow<2Good2-8High8-12Danger12+

Flow rate: 50.32 GPM

  • Water velocity is 20.6 ft/s, above the 8 ft/s guideline. High velocity causes erosion, noise, and water hammer risk.
  • Equivalent to 3,019 gallons per hour.
  • The pipe friction consumes 60.0 PSI of pressure over the specified length.

Next stepCross-check velocity against your pipe manufacturer rating, and allow extra pressure headroom for fittings (typically add 10 to 30 percent to the calculated pipe loss).

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