Looking to measure your PD yourself? Our free downloadable PD ruler is dead simple to use and can provide an accurate measurement. All you need is a printer!

What is a PD ruler?

A PD ruler is very simply a ruler designed specifically to measure your Pupillary Distance.
By printing it out and placing it carefully along your forehead, the ruler lets you measure the distance between the centre of your pupils in precise millimetres.

How to use our free downloadable PD ruler

First, prepare the ruler:

mouqy pd ruler


  • Click here to download our ruler PDF.

  • Print the PDF page without scaling, at 100% vertically.

  • Double-check the scale of the printed PD ruler by measuring it against a standard mm ruler, or a standard credit card (85mm).

  • Fold the ruler along the dotted line.


Then, measure your PD:


  • Position yourselfStand approximately 8 inches (20cm) away from a mirror in bright light, or ask someone to measure for you.

  • MeasureKeeping your face straight, place the ruler directly over the center of your right pupil so that the ruler is horizontal. You can place it against your forehead for more stability.

  • RepeatLook straight ahead and measure the distance between your left and right pupils. Repeat 3 times for accuracy and use the average for your final PD measurement.


What is PD (pupillary distance)?

PD stands for pupillary distance, and simply refers to the distance between the centres of each of your pupils. PD is measured in millimetres (mm) and is an important measurement that all eyewear manufacturers need in order to produce a pair of prescription lenses that can correct your vision properly.
In a perfect world, your PD measurement is included on the eyeglass prescription you receive from your eye doctor, or optician.
Unfortunately though, this isn’t always the case. Some opticians may even deliberately leave this information out, since they know that, by giving you your PD measurement, you’re able to go ahead and order glasses from another supplier. Thankfully, it’s easy enough to measure your own PD from the comfort of home.

What’s the difference between single PD and dual PD?

When you’re ordering a new pair of glasses, some eyewear retailers will let you input your PD measurement in one of two ways: single PD and dual PD.

  • Single PDThe total distance between your two pupil centres.

  • Dual PDThe distance from the middle of your head, to each of the centres of your pupil. This leaves you with two separate measurements.

Please note that our printable PD ruler is only for single PD readings – not dual PD.
Single PD measurements tend to be more commonly used, since these are used for less severe prescriptions such as single vision lenses or reading glasses. You can easily get this measurement by printing our PD ruler and following the instructions above.
If you’re getting an official eye prescription from an optometrist or ophthalmologist, it’s possible that they may give you a Dual PD measurement.

What are the average pupillary distances for adults?

The average range of pupillary distance for adults is between 54-74mm.
It’s always best to know your own personal PD, though in some cases, it may be possible to use a figure within the average PD range. However, this is only if you don’t require a strong prescription, and if you don’t have a particularly large or small head.
For example, someone who wears single vision lenses with a strength of less than +4.00 or higher than -4.00, and astigmatism lower than -2.00 may be able to get away with using the PD average measurements above.
However, we’d definitely recommend you take your PD measurements with the ruler above instead. It only takes a few minutes!

Are there other ways to measure PD?

If you’re looking for other ways to measure your PD besides using our PD ruler – no hard feelings!
You can also use a regular ruler – just bear in mind it can be a bit trickier to hold it against your face with one eye closed. You might want to rope in a friend to help you out. We’ve written more about this in our guide on how to measure your PD.

You’ve got your PD – now what?

Congratulations, now that you have your PD, you’re now equipped to order your next pair of glasses!
Why not start by exploring Mouqy’s own collection of eyeglasses?