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Water Pipe Flow / Velocity / Headloss Calculator

Calculate circular full-pipe velocity and Darcy-Weisbach major headloss from supplied flow, diameter, length and Darcy friction factor.

Major friction loss only. Darcy f is an explicit input; fittings, elevation, pump and network effects are outside V1.
01

Pipe inputs

No hidden friction-factor defaults.

Scenario
Darcy-Weisbach inputs
02

Pipe hydraulic result

Enter pipe inputs and calculate.

hƒ

Ready for calculation

Velocity and major headloss will appear here.

Methodology

Darcy-Weisbach major headloss

TOOL-010 uses V = Q/A with A = πD²/4, then hƒ = f(L/D)(V²/2g). Canonical gravity is g = 9.80665 m/s².

V1 inputs

Explicit friction factor

V1 intentionally does not infer f. This avoids hidden assumptions about roughness, fluid properties or pipe condition.

Worked example

For Q=0.05 m³/s, D=0.20 m, L=100 m and f=0.020: A=0.031415927 m², V=1.591549431 m/s, major headloss=1.291485671 m, gradient=0.012914857 m/m.

Limitations

This V1 calculates major friction loss only. The machine-readable loss scope is major-friction-only. It does not calculate fittings/valves, static elevation head, residual pressure, pump duty, surge or network hydraulics.

Source

Formula provenance is registered as SRC-DARCY-WEISBACH-TOOL010-001.