Enter the duct design flow (CFM) and the allowable leakage percent (%) into the Duct Leakage Calculator. The calculator will evaluate the Duct Leakage.

## Duct Leakage Formula

The following two example problems outline the steps and information needed to calculate the Duct Leakage.

DL = DF * AL / 100

Variables:

• DL is the Duct Leakage (CFM)
• DF is the duct design flow (CFM)
• AL is the allowable leakage percent (%)

To calculate the duct leakage, divide the duct design flow by the allowable leakage percentage over 100.

## How to Calculate Duct Leakage?

The following steps outline how to calculate the Duct Leakage.

1. First, determine the duct design flow (CFM).
2. Next, determine the allowable leakage percent (%).
3. Next, gather the formula from above = DL = DF * AL / 100.
4. Finally, calculate the Duct Leakage.
5. 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.

duct design flow (CFM) = 500

allowable leakage percent (%) = 3

DL = DF * AL / 100 = ?