Enter the peak systolic velocity and the end-diastolic velocity into the Calculator. The calculator will evaluate the Resistive Index.

## Resistive Index Formula

RI = (PSV - EDV) / PSV

Variables:

- RI is the Resistive Index ()
- PSV is the peak systolic velocity
- EDV is the end-diastolic velocity

To calculate Resistive Index, subtract the end-diastolic velocity from the peak systolic velocity, then divide by the peak systolic velocity.

## How to Calculate Resistive Index?

The following steps outline how to calculate the Resistive Index.

- First, determine the peak systolic velocity.
- Next, determine the end-diastolic velocity.
- Next, gather the formula from above = RI = (PSV – EDV) / PSV.
- Finally, calculate the Resistive Index.
- 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.

peak systolic velocity = 5

end-diastolic velocity = 14