Enter the total annular volume (bbls) and the total flow rate (bbl/min) into the Lag Time Calculator. The calculator will evaluate the Lag Time.

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## Lag Time Formula

The following two example problems outline the steps and information needed to calculate the Lag Time.

LT = AV / FR

Variables:

- LT is the Lag Time (min)
- AV is the total annular volume (bbls)
- FR is the total flow rate (bbl/min)

To calculate the lag time, divide the annular volume by the total flow rate.

## How to Calculate Lag Time?

The following steps outline how to calculate the Lag Time.

- First, determine the total annular volume (bbls).
- Next, determine the total flow rate (bbl/min).
- Next, gather the formula from above = LT = AV / FR.
- Finally, calculate the Lag Time.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

total annular volume (bbls) = 50

total flow rate (bbl/min) = 20

LT = AV / FR** **= ?