Free · Physics models
Straight Pipe Friction Pressure Drop
Relate pressure loss to Darcy friction factor, pipe size, length and fluid speed.
- Formula & worked example
- Private in your browser
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Calculator inputs
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How to use this calculator
- Enter the known values in the units shown. Results update as you type.
- Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
- Use the worked example to check the method. Reset restores the starting fields.
Private by default
Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.
Formula and method
pressure drop = 1000.0. This worked example uses the displayed units and declared assumptions.
pressure_drop = friction_factor*length*velocity*velocity*fluid_density/(2*diameter)
Worked example
Enter these known values and leave the other values blank.
- Darcy friction factor (f)
- 0.02
- Pipe length (L)
- 10 m
- Pipe diameter (D)
- 0.1 m
- Flow velocity (V)
- 1 m/s
- Density of fluid (ρ)
- 1000 kg/m³
- Pressure drop (ΔP)
- 1000 Pa
Assumptions and limitations
- Use the Darcy friction factor, which is four times the Fanning factor. Straight uniform pipe, incompressible steady flow and a supplied friction factor are assumed. Fittings, elevation and local losses are omitted.
- Clear an unknown to solve a supported inverse; keep known values fixed with locks. Singular or underdetermined inverses may remain incomplete.
Common questions
What assumptions apply?
Use the Darcy friction factor, which is four times the Fanning factor. Straight uniform pipe, incompressible steady flow and a supplied friction factor are assumed. Fittings, elevation and local losses are omitted.
Which unknowns can I solve?
Editable controls preserve the supported captured inverse branches. Clear the desired unknown and provide enough independent known quantities; singular or underdetermined inverses may remain incomplete.
References
Use the Darcy friction factor, which is four times the Fanning factor. Straight uniform pipe, incompressible steady flow and a supplied friction factor are assumed. Fittings, elevation and local losses are omitted. Clear an unknown to solve a supported inverse; keep known values fixed with locks. Singular or underdetermined inverses may remain incomplete.