How To Measure Your Pd How To Measure Your Pd

Measure your pupillary
distance (PD)

What is Pupillary Distance?

Pupillary distance (PD) measures the distance between the centers of your pupils. This measurement is used to determine where you look through the lens of your glasses and should be as accurate as possible.
Seems too technical? Don’t worry - measuring the PD is super easy with a ruler and some patience (plus with the help of a kind friend)

How To Measure Pupillary Distance Using Ruler or Card

Scale Method : Measuring your PD is extremely easy with a ruler and the help of a friend.
You simply have to stand in front of a mirror, take a ruler and measure the difference between the distance between the centre of your right and left eye’s pupil.Apart from a ruler, you can also use a measuring tape or an app on your phone.

1. Stand around 8 inches to 1 feet away from a mirror.

Place a ruler horizontally against your eyebrows. Close your right eye, then align the ruler’s 0 mm with the center of your left pupil.

2. Look straight, then close your left eye and open your right eye.

The mm mark that lines up to the center of your right pupil is your PD.

3. Leave it to us

If you are unsure about measuring it yourself, you can also take a measurement photo using which we’ll check the PD for you.

Some Additional Tips To Measure Pupillary Distance (PD)

  • Whilst the distance between your pupils is one length, you’ll have to halve it to work out the PD for each eye, e.g. if your PD is 60mm, your left and right eyes will be 30mm each.
  • If you can’t halve your PD to a round number, no problem - split them to the closest 0.5mm, e.g. if your PD is 60.5mm, fill in: right = 30mm, left = 30.5mm. We see this quite a bit so, don’t worry, we know how to deal with it.
  • The average PD is somewhere between 58-68mm. If yours falls outside this, or you have a prescription over +/-6 SPH, get in touch with us and we’ll give you a helping hand.
  • Visiting one of our stores? Easy, our retail assistants will measure your PD for you.

Why is Pupillary Distance Measurement Important?

If your PD isn’t right, it can cause eye strain, fatigue, or simply not being able to see properly. The higher your prescription, the bigger the effect an incorrect PD can have.

Your eyes should view the world through the best part of your lenses and since your pupils are in the middle of your eye, we make your lenses with that central point in mind. So, get measuring!

Don’t forget: if something doesn’t feel right, you can always contact us for corrections.

measure pupillary distance through Scale
measure pupillary distance through card
click picture

How To Measure Your PD!


Pupillary distance can be extremely important and if incorrect can cause dizziness, blurred vision and double vision.
The average adult’s PD is between 54-74 mm. For kids it is between 43-58 mm.
The pupillary distance measurement does not have to be 100% accurate. If you are not comfortable measuring your own PD, you can always ask your optometrist, or walk-in to our store. Our staff will be more than happy to help you with it.
The PD measurement can change for children as they grow. But once you reach adulthood, the pupillary distance usually stays the same.
While there are few tools to measure your PD online, it is much more accurate to do it at home yourself. And it is super easy as well! Here are the steps to measure your PD online:
  • Stand 12 inches or 30 cm away from a mirror
  • Look straight into the mirror and hold a millimetre ruler/scale flat against your eyebrows. You can also use an app on the phone if you don’t have a ruler.
  • Close your right eye and alight the 0 mm mark to the centre of your left pupil
  • Now close your left eye while keeping the right one open without moving the ruler
  • Find the mark corresponding to the centre of your left pupil. The measurement you get is your PD
  • Repeat the process a few times to make sure the number you get is consistent

If you can’t figure out how to measure your PD online, you can just take a close snap of your eyes with a millimetre ruler placed horizontally over them and send the picture to us. We will give you an exact measurement or you can visit our store to get it done physically.

You can use your 8.5 x 5.4 cm bank card to measure your PD without a ruler. Remove your glasses and sit in bright natural light. Hold the card against your forehead using two fingers. Look straight directly into the camera and take a snap. Send the picture to us and we’ll give you your PD or add it automatically to your order if you’re buying prescription glasses from us.
If your PD isn’t correct, it might affect your vision and give you eye strains. This is why you must make sure your PD is correct before you place an order for eyeglasses.
PD should be as accurate and exact as possible. If the lenses are not centred properly, it can cause visual discomfort. However, it doesn’t have to be 100% precise as a small margin for error. But, to get the best vision, it should be as close to the accurate number as possible.
You can measure pupillary distance using your glasses. For this, you’ll need to keep your glasses on. Close your right eye and put a mark on the left lens of your glasses falling in front of your left pupil. Now do the same with your right eye while keeping the left eye closed. Take off your specs and measure the distance between the two marks and you’ll get your PD.

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