# Difference between Fanning friction factor and Darcy friction factor

|Contents

## What is the Difference between Fanning friction factor and Darcy friction factor?

## Fanning friction factor

The Fanning friction factor is defined as follows:

f_{f} = f_{d} /4

Where;

f_{f} =Fanning friction factor

f_{d} =Darcy friction factor

## Darcy friction factor

The Darcy friction factor is defined as follows:

f_{d} = 4 * f_{f}

Where;

f_{f} =Fanning friction factor

f_{d} =Darcy friction factor

So, Darcy friction factor is 4 times higher than Fanning friction factor

## What about Moody chart?

The friction factor obtained from Moody chart is mainly the “Darcy Friction Factor”. So if we are taking about Moody Friction factor or Moody Friction Chart we are mainly referring to “Darcy Friction Factor”, we can calculate it from Colebrook–White equation when the flow is turbulent.

### Other Resources

- Pipe friction head loss calculations using Darcy-Weisbach equation
- Hazen-Williams equation for head loss calculations

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