Pipe Pressure Drop Calculator
Calculate friction loss in a pipe from flow rate, diameter, and length.
Result
Pressure drop
0.3727 bar
5.4055 psi
Head loss
3.8081 m
Velocity
2 m/s
Reynolds number
199,201.5968
Flow regime
Turbulent
Usage examples
Checking pressure drop for pump selection
Enter your target flow rate and pipe specs to calculate the friction-caused pressure drop, then use it to pick an appropriately-rated pump.
Comparing loss across pipe materials
See how pressure drop changes with pipe material (roughness) for the same flow rate.
Checking laminar vs. turbulent flow
Compute the Reynolds number to see whether your conditions are laminar or turbulent, and how adjusting velocity changes that.
Frequently asked questions
What formula does this use?
The Darcy-Weisbach equation, with the friction factor computed via the Swamee-Jain approximation, which avoids the iterative solving the classic Colebrook-White equation requires.
Can I calculate for fluids other than water?
Yes. Choose 'Custom' to enter density and viscosity directly for other fluids, like oil.
How is the roughness value chosen?
Selecting a pipe material applies a commonly-used absolute roughness value automatically. For materials with wide variance, like concrete, actual values can differ based on real-world condition.
Can I use this result directly for a real design?
This calculator only accounts for straight-pipe friction loss, not minor losses from valves and fittings. A real design needs to account for those additional losses too.