Enter the differential pressure (W.C.) and the cross-sectional area (ft^2) into the CFM From Differential Pressure Calculator. The calculator will evaluate the CFM From Differential Pressure. 

CFM From Differential Pressure Formula

The following two example problems outline the steps and information needed to calculate the CFM From Differential Pressure.

CFM = 4005 * SQRT( dP) * A

Variables:

  • CFM is the CFM From Differential Pressure (ft^3/min)
  • dP is the differential pressure (W.C.) 
  • A is the cross-sectional area (ft^2) 

How to Calculate CFM From Differential Pressure?

The following steps outline how to calculate the CFM From Differential Pressure.


  1. First, determine the differential pressure (W.C.). 
  2. Next, determine the cross-sectional area (ft^2). 
  3. Next, gather the formula from above = CFM = 4005 * SQRT( dP) * A.
  4. Finally, calculate the CFM From Differential Pressure.
  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.

differential pressure (W.C.) = .50

cross-sectional area (ft^2) = 2.5

CFM = 4005 * SQRT( dP) * A = ?