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Enter the flow rate, pipe inner diameter, length and fluid properties to get the friction pressure drop, head loss, velocity, Reynolds number and Darcy friction factor as you type. Defaults are the industry benchmark for 20 °C water in a DN100 steel pipe.
Create a free account and these inputs open as a new project in the workspace, where you can save, edit and export a Word / PDF calculation report.
Results are for reference; check them against the applicable engineering codes. Everything is calculated in your browser and your inputs are not uploaded.
Inputs: Q = 50 m³/h, D = 100 mm, L = 100 m, ε = 0.045 mm, ρ = 998.2 kg/m³, μ = 1.0016 cP
| Pressure drop ΔP | 29.5 kPa |
|---|---|
| Head loss h | 3.013 m |
| Mean velocity v | 1.768 m/s |
| Reynolds number Re | 176 239 |
| Darcy friction factor f | 0.0189 |
| Flow regime | Turbulent (Swamee–Jain) |
The example matches industry benchmark GC-IND-DW-001 in our repository (expected values derived independently with 50-digit decimals and checked by automated tests).
Darcy–Weisbach is based on fluid mechanics and works for any Newtonian fluid and flow regime; Hazen–Williams is an empirical formula for turbulent water at ambient temperature only. This tool uses Darcy–Weisbach.
Colebrook is implicit and needs iteration; Swamee–Jain is an explicit approximation within about 1% of Colebrook in the usual range, so results update instantly. The page warns you when you are outside that range.
From the Reynolds number Re = ρvD/μ: below 2000 the flow is laminar and f = 64/Re; 2000 to 4000 is transitional and uncertain; above 4000 it is turbulent.
No, this tool calculates straight-pipe friction only. Add minor losses with K values or equivalent lengths; in the workspace you can build them into one calculation module.
Yes. Click "Save to project / export report" and create a free account; your inputs open as a new project in the workspace, where you can save, edit and export a Word / PDF report.
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