Pipe Pressure Drop Calculator
Darcy-Weisbach friction loss in pipes
📚 Learn more — how it works, FAQ & guide Click to expand
Learn more — how it works, FAQ & guide
Click to expand
Pipe Pressure Drop Calculator (Darcy-Weisbach)
Friction loss in pipes: Reynolds number → friction factor (Colebrook approximation) → pressure drop and head loss. Standard fluid mechanics for HVAC, hydraulics, process design.
How to use this tool
- 1
Pipe + fluid
Diameter, length, fluid props.
- 2
Flow rate
Volume per time.
- 3
See ΔP + head loss
Darcy-Weisbach friction calculation.
Frequently Asked Questions
Darcy-Weisbach equation?
ΔP = f × (L/D) × (ρV²/2). Where f = friction factor, L = length, D = diameter, ρ = density, V = velocity. f comes from Moody diagram (Reynolds + roughness).
Common roughness values (mm)?
Smooth (PVC, drawn copper): 0.0015. Commercial steel: 0.045. Galvanized iron: 0.15. Concrete: 0.3-3.0. Old cast iron: 0.5+.
When does this fail?
Two-phase flow, compressible gas at high velocity (>0.3 Mach), non-Newtonian fluids. For those, use specialized models. Single-phase liquid + low gas: D-W is solid.
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