How to find your pupillary distance (PD)

What is Pupillary Distance (PD)?

Pupillary Distance (PD) is the space between the centers of your pupils, measured in millimeters. This measurement helps us align your lenses perfectly with your eyes—ensuring optimal clarity and comfort when you wear your glasses.

Having the correct PD ensures:

  • Your vision is clear and sharp
  • Your lenses sit correctly in your frames
  • You avoid eye strain or discomfort

How to Measure Your PD

Option 1: Measure with a Ruler & Mirror

What you’ll need:

  • A millimeter (mm) ruler
  • A mirror

Steps:

  1. Stand about 8 inches (20 cm) away from a mirror.
  2. Hold the ruler against your brow, just above your eyes.
  3. Close your right eye and align the 0 mm mark with the center of your left pupil.
  4. While keeping the ruler still, close your left eye and open your right eye.
  5. Look straight and note the measurement that lines up with the center of your right pupil.

That is number is your PD!

You can also get a friend to help, its very easy!

Option 2: Use a mobile app

What you'll need:

  • A smartphone
  • The GlassesOn app

GlassesOn is the leading mobile app for measuring your PD. Its free and clinically proven.

Just follow the instructions on the app or watch the video below to measure your own PD using a clinically proven app.

Download for AndroidDownload for Apple

GlassesOn App Video