Pipe Pressure Calculator

Estimate pressure loss through a pipe from flow rate, pipe diameter, pipe length, fluid density, viscosity, and roughness. This pipe pressure calculator shows pressure drop in PSI, kPa, bar, feet of head, and meters of head.

Calculate Pipe Pressure Drop

Darcy-Weisbach: pressure drop = friction factor × length/diameter × density × velocity² ÷ 2
Your result will appear here.

How the pipe pressure calculator works

Flow rate:
Enter the amount of fluid moving through the pipe. Higher flow usually creates more pressure loss.

Pipe size and length:
Enter the inside diameter and total pipe length. Smaller diameter and longer length increase pressure drop.

Fluid and roughness:
Select fluid density, viscosity, and pipe roughness. Rougher pipe and thicker fluids usually increase pressure loss.

Why use a pipe pressure calculator?

A pipe pressure calculator is useful for plumbing estimates, irrigation lines, water systems, pump sizing, pressure loss checks, piping design, fluid flow examples, and comparing pipe sizes.

This calculator estimates pressure drop through a straight pipe using Darcy-Weisbach style friction loss.

Pipe pressure formula

This calculator estimates pipe pressure loss using:

ΔP = f × (L ÷ D) × (ρ × v² ÷ 2)

Pipe pressure calculator tips

Frequently asked questions

How do you calculate pipe pressure drop?

Pipe pressure drop can be estimated from pipe length, diameter, flow velocity, fluid density, viscosity, and pipe roughness. This calculator uses a Darcy-Weisbach style method.

Does pipe diameter affect pressure loss?

Yes. Smaller inside diameter greatly increases velocity and pressure drop for the same flow rate.

Does longer pipe reduce pressure?

Yes. Longer pipe creates more friction loss, which reduces pressure at the outlet.

What is minor loss in pipe pressure?

Minor loss is extra pressure loss caused by fittings, bends, valves, entrances, exits, filters, and other restrictions.