Darcy Weisbach Calculator

Find pipe friction head loss with the Darcy–Weisbach equation.

Friction factor

Pipe length

Pipe diameter

Flow velocity

Gravity (m/s²)

Head loss 2.039

Formula: h_f = f·(L/D)·(v² ÷ 2g)

Step-by-step with your numbers:

1. Values used:

2. Friction factor = 0.02

3. Pipe length = 50

4. Pipe diameter = 0.1

5. Flow velocity = 2

6. Gravity = 9.81 m/s²

8. Head loss = 2.039

Did we solve your problem today?

Darcy–Weisbach gives the energy lost to friction as fluid flows through a pipe.

The math behind it

h_f = f·(L/D)·(v²/2g). Longer, narrower, faster flows lose more head.

f = 0.02, 50 m, 0.1 m dia, 2 m/s → about 2.04 m.

How do I get f?

From the Reynolds number and pipe roughness (Moody chart) or the friction-factor calculator.