Calculate estimated pressure drop through a water pipe based on flow rate, pipe diameter, pipe length, and pipe material. Estimate PSI loss, head loss, friction loss per 100 feet, water velocity, and outlet pressure for plumbing, irrigation, pump, and water supply planning.
Pipe pressure drop:
The calculator estimates friction loss using a Hazen-Williams style water flow equation, then adds elevation loss and fitting allowance.
Outlet pressure:
The calculator subtracts total pressure drop from starting pressure to estimate remaining pressure at the end of the pipe run.
Maximum pipe length:
The calculator estimates how long the pipe can be before reaching the allowed pressure drop.
A pressure drop calculator helps estimate whether a pipe run can deliver enough water pressure after friction, fittings, and elevation changes.
It can help compare PSI drop, head loss, flow rate, water velocity, friction loss per 100 feet, outlet pressure, pipe length, and pipe diameter.
Your result shows estimated pressure drop through the pipe, outlet pressure, head loss, water velocity, friction loss per 100 feet, and equivalent pipe length. These are planning estimates only. Actual pressure drop can vary based on fittings, valves, pipe condition, pipe material, water temperature, elevation, and the full plumbing system layout.
Pressure drop is the amount of pressure lost as water moves through pipe, fittings, valves, elevation changes, and restrictions.
Pressure drop is commonly caused by pipe friction, small pipe diameter, long pipe runs, high flow rates, fittings, valves, filters, and elevation gain.
Yes. A larger pipe usually reduces velocity and friction loss, which can lower pressure drop for the same flow rate.
No. This calculator gives a planning estimate. Final plumbing design should account for local code, manufacturer data, fittings, valves, elevation, pump curves, and complete system design.