Find it on your prescription, the P.D can be found toward the bottom of your prescription. PD value ranges between 50 mm to 70mm with most common being 62. If your PD contains two numbers, for example 62/60, this means the distance PD is 62 and the near PD is 60. The near PD is only required when ordering bifocals, progressives.
Measure it yourself with 2 simple steps:
Step 1: Begin by placing a millimeters ruler on your nose so that the starting point of the ruler is at your right or left eye pupil.
Step 2: You can either use a mirror or ask a friend to measure the distance between the left and right pupil. Make sure you look straight ahead (for accuracy repeat several times).
These two steps are very simple, easy and more accurate than just using an average PD. We strongly recommend obtaining your prescription from your eye doctor or local optician if you have a progressive or bifocal prescription.