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) 

To calculate the ERO, divide the volume flow rate by the maximum velocity.

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 = ?