Enter the volume flow rate (ml/s) and the maximum velocity (cm/s) into the ERO Calculator. The calculator will evaluate the ERO. 

ERO Formula

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

ERO = VFR / Vm


  • ERO is the ERO (cm^2)
  • VFR is the volume flow rate (ml/s) 
  • Vm is the maximum velocity (cm/s) 

How to Calculate ERO?

The following steps outline how to calculate the ERO.

  1. First, determine the volume flow rate (ml/s). 
  2. Next, determine the maximum velocity (cm/s). 
  3. Next, gather the formula from above = ERO = VFR / Vm.
  4. Finally, calculate the ERO.
  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.

volume flow rate (ml/s) = 30

maximum velocity (cm/s) = 20

ERO = VFR / Vm = ?