PSI to GPM Calculator

Calculate water flow rate in gallons per minute from pressure measurements using Bernoulli's equation

PSI to GPM Conversion

Tank Pressure (P₁)

PSI

Pressure inside the tank or system

Exit Pressure (P₂)

PSI

Atmospheric pressure (14.7 PSI at sea level)

Pipe Specification Method

Pipe Diameter

inches

Internal diameter of the pipe

Fluid Density

lb/ft³

Water at room temperature: 62.4 lb/ft³

Output Unit

Flow Rate Results

1411.3

GPM

84679

GPH

3.144

ft³/s

Calculation Details

Pressure Difference: 57.3 PSI

Flow Velocity: 92.24 ft/s

Pipe Area: 0.0341 ft²

Primary Result: 1411.3 GPM

Common Pipe Sizes

1/2" pipe

Typical pressure: 30 PSI

3/4" pipe

Typical pressure: 25 PSI

1" pipe

Typical pressure: 20 PSI

1.25" pipe

Typical pressure: 18 PSI

1.5" pipe

Typical pressure: 15 PSI

2" pipe

Typical pressure: 12 PSI

2.5" pipe

Typical pressure: 10 PSI

3" pipe

Typical pressure: 8 PSI

Bernoulli's Equation

v = √(2 × ΔP / ρ)

Q = A × v

v: Flow velocity (ft/s)

ΔP: Pressure difference (PSI)

ρ: Fluid density (lb/ft³)

Q: Flow rate (GPM)

A: Cross-sectional area (ft²)

Quick Reference

Standard Conditions

Atmospheric pressure: 14.7 PSI

Water density: 62.4 lb/ft³

Temperature: 68°F (20°C)

Conversion Factors

1 ft³/s = 448.83 GPM

1 GPM = 60 GPH

1 PSI = 144 lbf/ft²

Typical Applications

Fire hydrants: 80-120 PSI

Garden hose: 30-50 PSI

Household plumbing: 40-60 PSI

Understanding PSI to GPM Conversion

What is PSI?

PSI (Pounds per Square Inch) measures pressure - the force applied over a specific area. It indicates how much force is pushing the fluid through the system.

What is GPM?

GPM (Gallons per Minute) measures flow rate - the volume of fluid moving through a pipe in one minute. It tells us how much liquid is actually flowing.

Why Can't We Convert Directly?

PSI and GPM measure different physical properties. Pressure doesn't directly equal flow rate. We need additional factors like pipe size and fluid properties to calculate flow from pressure.

Bernoulli's Principle

Our calculator uses Bernoulli's equation, which relates pressure, velocity, and elevation in fluid flow. For horizontal pipes, higher pressure differences create higher flow velocities.

Key Assumptions

•Incompressible fluid (liquids like water)
•Steady flow conditions
•Negligible friction losses
•Horizontal pipe (no elevation change)

Note: Real-world results may vary due to pipe friction, fittings, and other factors not accounted for in this simplified calculation.