by Jamie Bartlett

What is my pupillary distance?


Some opticians have been known to charge a fee for this very basic measurement.

If you can use a ruler, your'e already halfway there.

Pupillary distance (PD) is the length, in mm, between the centre of your pupils. This measurement determines where the centre of your lenses are, according to your eyes.Via your biennial eye exam, your prescription doesn't always state your PD.

On this occasion, the following steps will show you how to measure it yourself and why you certainly shouldn't be charged for it.


Content: Measuring your PD with help | Measuring your PD without help | Measuring your PD using an app | What's a mono PD? | Standard PD sizes



Easy ways to measure your pupillary distance



Group of 1800's street children playing together.


Grab a friend and the nearest ruler.

Instruct them to carefully hold the ruler across your brow.

Using mm, your assistant can simply measure between your pupils.

Note your PD on your phone or write it on your prescription paper.



    Paul Smith holding a mirror looking into it.


    Stand about a foot away from a mirror.

    Hold the ruler across your brow.

    Close your right eye then align the ruler’s 0 mm with the center of your left pupil.

    Look ahead then close your left eye and open your right eye.

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


      Using an iPhone app to measure your pupillary distance.


      Free : Link to free app.

      £0.99 : Link to paid app.





      What's the difference between PD and Mono PD?



      An illustration of measuring your pupillary distance.


      If you require single vision lenses, you’ll only need the total distance between your pupils.

      For adults, this number will be in the region of about 60mm in total.




      An illustration of measuring your mono-pupillary distance. (Mono PD)

      MONO PD

      If you require multi-focal lenses such as progressives, bifocals and trifocals, you will require what is called your Mono PD.

      This is the distance from the centre of your face to each individual pupil.

      These number can be different such as 32.5mm and 33mm.




      Image of a steel ruler.


      Without your PD, opticians can use average male/female PD sizes when fitting your prescription. It's always better to have your personal PD but these averages can be used as a general guide.

      Male : 64mm

      Female : 62mm



        Jamie Bartlett
        Jamie Bartlett

        Co-founder of Banton Frameworks.

        Also in How To

        How to choose glasses: for your eye colour

        by Jamie Bartlett

        Go into greater detail and learn how to choose glasses based on your eye colour.
        Read More
        How to adjust glasses: a helpful guide

        by Jamie Bartlett

        Need help adjusting your glasses frame? Follow this simple guide to fine-tune your spectacle frame and get them fitting perfectly.
        Read More
        How to use your rubber band.

        by Jamie Bartlett

        With our packaging, our bespoke rubber bands can be used for a multitude of secondary tasks. Here's some handy ideas for a second lease of life.
        Read More