How to Measure Pupillary Distance | What is My PD?

PD is an essential part of ensuring your prescription glasses are sized correctly for your face. Your Pupillary Distance, or PD for short, is the distance between the center of one pupil to the center of the other pupil. We use this measurement to prepare and process your specific prescription glasses order. Each pair of prescription glasses we prepare is specific to each individual’s PD. Your PD measurement is matched so that it is the same as the distance between the optical centers of the glasses’ lenses.  Correct Pupillary Distance (PD, Pupil Distance), is even more important when it comes to high powered lenses.  

Below are three different methods you can choose from to find your Pupil Distance. 

1. Get it from Your Optician

 One way you can get your PD is by requesting it from your optician when you go in to receive your prescription. They are required by law to provide this information to you but it is possible they will not provide it unless you specifically request it during your visit. As an adult, your PD will never change. So even if your prescription changes you will not need to measure your PD every time you buy prescription glasses.

Below is an example of where you can find your PD written on your Eyewear Prescription:

 2. How to Measure Pupillary Distance at Home

 You can easily take a measurement of your PD by yourself or with a friend’s help. Follow these instructions:

  1. Take a ruler that has millimeter measurements on it (or Download our PD Ruler) and place it on your nose so that the starting point of the ruler is exactly at the center of one eye pupil
  2. Making sure the ruler is straight, stand in front of a mirror or have a friend measure the distance from the center of the first pupil to the center of the second pupil while you look straight ahead
  3. Because this measurement is so important to the accuracy of your prescription glasses, we recommend taking this measurement at least 3 times. If these measurements vary, use the average as your PD.


3. Let SaltCityOptics Measure Your PD using SaltCityOptics’ PD-Pro Method

Having your Pupillary Distance measured by SaltCityOptics is a snap. After you place your order follow these steps so we can accurately measure your PD for you.

  1. Remove any eyeglasses or sunglasses that you are wearing
  2. Grab one of your credit cards or any card with a magnetic strip (holding your finger over the credit card number for security) and hold it over your chin in the center of your face as seen in the photo below:
  1. Take an image of yourself holding the credit card in front of your face, making sure to capture your entire face in the photo.
  2. Send it to us your image with your order in the subject line. You can send it us by text message to, email to or fax 1-888-507-1227

Your Pupillary Distance will be confirmed within 24 hours of receiving your image. Once your PD is confirmed, we will then complete your order and send it to be processed. One of our trained representatives will contact you if there are any questions regarding your PD measurement.