engineering

Darcy-Weisbach Calculator

Calculate head loss and pressure drop in pipes using the Darcy-Weisbach equation with friction factor

Darcy-Weisbach Calculator

h_f = f·(L/D)·(v²/2g)  ·  ΔP = ρgh_f

Calculate friction factor from Moody chart

Laminar: f = 64/Re · Turbulent: use Moody toggle above

Results

Head Loss h_f

4.0775 m

Pressure Drop ΔP

39.928 kPa

= 39928 Pa

Friction Factor f

0.02000

Velocity

2.0000 m/s

Formula

h_f = f·(L/D)·v²/(2g) = 0.02000·(100/0.1)·2.000²/(2×9.81)

= 4.0775 m

How to Use This Calculator

1

Enter pipe geometry

Input pipe inner diameter, length, and roughness height in your preferred units.

2

Enter flow conditions

Input fluid velocity or flow rate, plus fluid density and dynamic viscosity (or select a fluid preset).

3

Read head loss and pressure drop

The calculator computes friction factor, head loss (hL = f·L/D·V²/2g), and pressure drop (ΔP = f·L/D·ρV²/2).

Formula Reference

Darcy-Weisbach Equation

h_L = f · (L/D) · (V²/2g)

Variables: h_L = head loss, f = Darcy friction factor, L = pipe length, D = pipe diameter, V = average velocity, g = gravitational acceleration

Pressure Drop

ΔP = f · (L/D) · (ρV²/2)

Variables: ΔP = pressure drop, ρ = fluid density

When to Use This Calculator

  • •Use the Darcy-Weisbach Calculator when solving homework or exam problems that require quick numerical verification of your hand calculations.
  • •Use it during the design phase to rapidly iterate on parameters before running detailed finite element simulations.
  • •Use it when reviewing a colleague's calculation or checking a vendor's data sheet for plausibility.
  • •Use it to generate reference data for a technical report or presentation without manual computation.

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