Enter the equivalent circulating density, static mud weight, and all other operating pressures into the calculator to determine the EMW.

EMW Formula

The following formula is used to calculate an EMW.


  • Where EMW is the equivalent mud weight
  • MW is the static mud weight
  • ECD is the equivalent circulating density
  • AOPE is all other pressure effects

To calculate the equivalent mud weight (EMW), add together the static mud weight, equivalent circulating density, and the sum of all other pressure effects.

What is EMW?


EMW, short for equivalent mud weight, is a measure of the total pressure in complex well-drilling.

How to calculate EMW?

Example Problem:

The following example outline how to calculate EMW.

First, determine the static mud weight. For this example, the static mud weight is 9.2 ppg.

Next, determine the equivalent circulating density. In this case, the ECD is measured to be 5 ppg.

Next, determine the AOPE. All other pressures are found to be 1.5 ppg.

Finally, calculate the EMW using the formula above:


EMW = 9.2 + 5 + 1.5

EMW = 15.7 ppg