How to Measure Your Pupil Distance

What is my PD/Pupil Distance and why is it important?

Your PD or Pupillary Distance is required to make sure that you are looking through the correct area of the lens when you wear your glasses. It is more important to get this measurement as accurate as you can when buying glasses with a higher prescription. With lower/weaker prescription lenses the pupil distance does not need to be so accurate.

It takes seconds to measure your PD.  An optician will do it for you very quickly, but you should take slightly more care when doing it yourself.

Measure it three times to make sure. It will help if you also get a friend to double check for you.

How to measure your DISTANCE PD

Measuring on your own – you will need…

  • A mirror
  • A ruler – with increments in mm
  • A steady hand and patience
  • Measure your PD without your glasses on – you may need a friend to help if you cannot see the ruler clearly
  1. Stand at half of an arms length (roughly 30cm) away from the mirror.
  2. Place the ruler against your forehead with measurements facing the mirror.
  3. Position the ruler so that zero is directly above the center of one of your pupils.
  4. Now read the measurement or mark the ruler at the point directly in the center of your opposite pupil.
  5. Repeat a minimum of three times.
  6. Note the measurement in mm.
  7. This is your PD/Pupillary Distance.

Getting a friend to help you

Step 1 – Aerial View

Measuring your pupil distance PD

  1. Sit at arms length while facing each other with your eyes level (not looking up or down).
  2. Your friend should close their left eye.
  3. They should place the ruler upside down against your forehead so that the mm units are closest to your eye with the zero above your left pupil.
  4. Look into their right eye, without moving your head, while they position the ruler at zero above your left pupil.

Step 2 – Aerial View

Measuring your pupil distance PD

  1. Now your friend should open their left eye and close their right eye
  2. Without moving your head, look into their left eye
  3. Your friend should now read the measurement where falls through the center of your right pupil.
  4. Repeat Steps 1 and 2 three times to ensure you have an accurate result.

PD’s usually fall between 54 and 74 mm. The average is 60mm for women and 64mm for men, but don’t worry if yours is different to the average!

How to measure your READING PD

You will not be able to measure your reading PD on your own. You will need a friend to help you.

Step 1 – Aerial View

Measuring your pupil distance PD

  1. Sit at arms length while facing each other with your eyes level (not looking up or down)
  2. You or your friend should hold a pencil at reading distance from your face, at eye level, roughly half way between you and your friend.
  3. You should now focus on the pencil and do not move your eyes from the pencil while your friend is measuring.
  4. Your friend will now do the same as they did to measure your distance PD.
  5. They should close their left eye and place the ruler against your forehead with zero the ruler above your left eye.
  6. Open their left and close their right eye and take the measurement above your right eye.
  7. This is your reading PD. Repeat three times for accuracy.

Your reading PD will, on average, be 3mm or 4 mm narrower than your distance PD. We still advise you to measure it as it will give a more accurate result.