What Is Pupillary Distance(PD)?

Pupillary Distance (PD) is the distance, in millimeters, between the center of one pupil to the center of the other. The PD is needed to manufacture your eyeglasses because it determines the exact optical center of the lens, which is the point where you look through the lens.

Printable PD ruler

Print this page on A4 (without scaling, at 100%. ) Use PD ruler at the bottom of the page. Recommend to use a physical PD ruler or consult your ophthalmologist.

Steps to measure your PD

Note: The average PD is between 54 and 78mm. Might be a bit different compared to practical measurements. Please measure your PD 2-3 times to ensure you get the accurate results.


Position yourself arm’s length from your friend or yourself approximately 8 inches (20cm) away from a mirror. Please measure your PD 2-3 times to ensure you get accurate results.


Close your right eye and align the 0 mm over the center of your left pupil.


Close your left eye and note the reading directly over your right pupil. That will be your Total PD.


You also need to measure the distance from two pupils to the center of your nose respectively to make sure that if you have two PDs (OD & OS).