About this tool
Velocity, Reynolds number, friction factor, head loss and pressure drop by Darcy–Weisbach.
v = Q/A; h_f = f·(L/D)·v²/(2g); f by Swamee–Jain (Colebrook approximation), 64/Re if laminar.
Formula: h_f = f·(L/D)·v²/(2g) Δp = ρ·g·h_f
Example: Flow rate (L/s) = 5, Internal diameter (mm) = 100, Pipe length (m) = 100, Absolute roughness ε (mm) = 0.045 → Head loss (m) = 0.446, Velocity (m/s) = 0.637.
Straight pipe only: fittings, minor losses and pump curves are excluded. Water defaults are shown in the fields.
Quick steps
- Enter your values — every field shows its unit.
- Press Calculate (or Try an example to see how it works).
- Read the results and copy them if you need them elsewhere.
The calculation runs in your browser. Nothing you type is sent to 1CLIK.
FAQ
How does the Pipe Flow & Pressure Loss work?
v = Q/A; h_f = f·(L/D)·v²/(2g); f by Swamee–Jain (Colebrook approximation), 64/Re if laminar.
What should I keep in mind?
Straight pipe only: fittings, minor losses and pump curves are excluded. Water defaults are shown in the fields.
Is my data sent anywhere?
No. The numbers stay on your device; the page only shows the result.