PSI to GPM Calculator

Estimate GPM from PSI for a given orifice or pump curve.

Flow rate (GPM) 187.84

Formula: GPM ≈ 29.7 × D² × √PSI (sharp orifice)

Step-by-step with your numbers:

1. Values used:

2. Orifice/hole diameter = 1

3. Pressure = 40 psi

5. Flow rate = 187.84GPM

Did we solve your problem today?

A rough estimate of flow through a sharp-edged orifice. Not a substitute for a pump curve.

The math behind it

GPM ≈ 29.7 × diameter² × √PSI (for a sharp-edged orifice discharging to atmosphere).

1 in orifice at 40 psi → ~188 GPM.

Exact?

No — it's a hydraulic estimate; real flow depends on geometry and losses.