Measure PD Measure PD


Don't have a PD value on your prescription? No problem you can measure it on our website by using only a card with a magnetic stripe. Watch the video and learn how to do it.

When you get your eyes examined by a professional, your eye card or prescription will usually contain the PD measurement. But if for some reason you have to measure it yourself, follow the instructions below for the most accurate results.

What is Pupillary Distance?

Pupillary distance (PD) measures the distance between the centers of your pupils. The average adult’s PD is between 23-37 mm and the average for kids' PD is between 22-29 mm.

Your eye doctor will usually measure your PD during an eye exam. However, if the PD value was not given to you, the below 5 steps will help you measure it yourself.

Why do we need your PD?

Prescription lenses have an “optical center,” which is determined by pupillary distance. Pupillary distance determines where you look through the lens and should be as accurate as possible. If the PD value you provide is wrong, this can affect the quality of your vision.

measure pd distance


If your PD was not measured at your eye exam, then you can simply measure it yourself. There are two simple options on our website. The first one is to measure it with your camera by using a card with a magnetic stripe see the video . The second option is to measure it by using a ruler – this simple procedure is described below.

1. Find a millimeter ruler for measurements or print the ruler here (link) . You will also need a mirror or a friend.

2. If using a mirror, try to look into the distance as you measure. If a friend is taking your measurements, try to look past them into the distance to avoid the result being too narrow.

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3. Hold the ruler against the bridge of your nose and line up the middle of your left pupil with the 0 line of the ruler. You can now measure the distance between your pupils!

4. Measure across to the middle of your right pupil, still looking into the distance. Your PD should be between 46 and 74. Then divide this number by 2 to get a PD of each eye.

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5. Repeat these steps 2 to 3 times to get a consistent number.


Single vs Dual PD

Dual PD is the measurement of the center of each pupil to the bridge of the nose. Single PD is the total distance between the center of both pupils. We recommend measuring dual PD. This is why:

Dual PD is believed to be the most accurate since many people have different distances between their nose and pupil on each eye.

PD is especially critical when you are ordering progressive lenses, which requires precise lens- to-pupil alignment to ensure comfortable vision at all distances.

measure dual single pd

Now that you have your eye test results and PD measured, you are ready to explore our glasses and try them on with the virtual mirror! If you have any additional questions, we'll be glad if you write us on