How to measure your pupillary distance

Measuring your pupillary distance at home is required to choose the right eyeglass frame size online. This measurement helps to find the right frame that keeps your eyes in the centre of the frame. Pupillary distance is a technical term that tells the distance between the pupils of both eyes.

There are multiple methods of measuring your pupillary distance that we discussed below. Also, we attached a free printable PD ruler for you to determine your PD distance.

What is Pupillary Distance?

Pupillary distance (PD for short) is the length, in mm, between the centre of your pupils.

PD is used to keep your prescription lenses properly aligned with the centre of your eyes.

Frustratingly, your pupillary distance on prescription papers isn’t always stated.

Type of Pupillary Distance

You can divide this pupillary distance into two parts. Single PD and dual PD.

Single PD = the total distance between the centre of your pupils.

Dual PD = the separate distances between the bridge of your nose and the centre of your pupils. Binocular PD does not reduce eyestrain, but it is good to consider.

 

 

How to Measure Pupillary Distance At Home

Measurement of pupillary distance is really easy. You can do it at home with just a ruler. If you don’t have a ruler, then there are multiple other ways to identify this distance. However, these steps can include several nuances and details.

 

 

 

 

Method 1: Using our Free PD ruler.

We've designed a free printable PD ruler to measure your pupillary distance at home. This makes the job much easier and gives a more accurate result, especially if you're doing this alone.

To measure your pupillary distance, use a ruler and position yourself in front of a mirror.

• Download and print this free PD ruler designed by Banton.
• Locate the V slot over your nose to find your facial centre.
• Using a mirror, check where your pupil aligns with the mm increments.
• It's easier to close one eye to see each opposite eye's PD.
• Note your measurements.

 

 

 

 

Method 2. What about a regular ruler?

Ok , you can use a regular ruler for this job.

However, it's pretty fiddly to hold the ruler still on your brow and will probably give you inaccurate results.

Steps to identify the Pupillary distance using a ruler

 

• Steady as you can, hold the ruler across your brow.
• Point the mm increments downward.
• Close your right eye then align the 0mm mark with the centre of your left pupil.
• Look ahead then close your left eye and open your right eye.
• The mm line that lines up to the centre of your right pupil is your total PD.

 

 

Method 3: How to measure pupillary distance using old glasses

This is a classic move.

You’ll need help from a friend on this one so it’s good to ask nicely.

• Grab your old glasses and a non-permanent marker pen.
• Get your partner to mark a small dot where your pupil is behind the lens.

• Check the total PD distance between the dots of your lens.

 

 

 

Method 4: Mobile app.

If you don’t have a ruler, a printable machine, and older glasses, then you can consider using a mobile app. We’ve done the hard work for you.

Here’s a free pupillary distance app you can download.

Check it out here

 

 

 

Method 5: Your prescription may already have it

Take a good look at your prescription paper.

Excusably, you might have overlooked your PD as it can sometimes be sneakily tucked away without realising it. It might even be on the reverse-side of the paper.

If your PD measurement is there, it’ll appear as one or two numbers.

• If it’s one number, it should be around 64mm or so.
• If it’s stated as two separate numbers, they should be around 32mm.

 

The average PD for men and women can vary between a minimum of 58mm and 73mm. 

 

 

 

How important is the PD for glasses?

To ensure that the centre of your lens aligns with the centre of your eye, your PD measurement is pretty important.

It’s safe to say that guessing your PD is a big no no, especially after reading the steps we’ve shown you above.

But let’s not freak out about this one guys.

Sure, you don’t want to give us the wrong pupillary distance… but think about it. Your glasses can sit ever slightly ‘off’ on your face so pin-point accuracy is perhaps a little bit overkill.

Heck, with the instructions above, you know what you’re doing. You’ll nail it.

 

What If Your Pupillary Distance Has Two Numbers

Your prescription paper may use dual pupillary distances as standard.

These two measurements can be added together if a total PD is required. This is usually for single vision glasses wearers.

However, if you require complex or strong prescription lenses such as varifocals, These two measurements can be added together if a total PD is required.

This lets us that your lens centres are as accurate to the centre of your pupil as possible. Varifocal glasses have a higher tolerance of accuracy as they are a more complex lens type.

Generally, total pupillary distances or average PD’s are considered as insufficient for varifocal prescriptions.

You can measure your mono PD(the PD for each eye) yourself with a basic ruler, but we suggest you use our free PD ruler which locates onto the centre of your nose for a more accurate result.

 

 

 

My Mono PD’s are slightly different?

Don’t worry, most people have a slightly asymmetrical head.

In fact, the most attractive celebrities have facial asymmetry… phew.

Your mono PD’s will vary ever so slightly. For example, your right eye Mono PD could be 32.5mm and your left eye could be 33mm.  

This small variance is completely normal and nothing to be concerned about.

 

 

What is the average PD?

If you wear single vision glasses, it can be okay to use average PD’s.

But the problem with average?

It’s… average.

You’re better taking a few minutes to get a proper measurement using our advice above. However, if you’re cool with average, here’s the average PD for adult men and women.

• Average PD for men: 64mm
• Average PD for women: 62mm

Frequently Asked Questions

How Are Mono and Dual Pupillary Distances Written on a Prescription?

A single PD is written as one number (in millimetres). A dual PD is written as two separate numbers, one for each eye. These are often labelled as ‘Right’ and ‘Left’, or sometimes as ‘OD’ (for the right eye) and ‘OS’ (for the left eye).

Do You Need PD for Sunglasses?

Your PD (pupillary distance) is important for all prescription eyewear because your eyes should be looking through the exact centre of your corrective lenses. This ensures proper vision correction and comfort. However, pupillary distance is not necessary if you are ordering non-prescription sunglasses.

What is the Average Pupillary Distance?

The average pupillary distance is typically between 48mm and 73mm (from children to adults). Everyone's eyes are different, and your PD might be different from the average person's measurements. It is important to check your specific PD measurement accurately for proper eyewear fitting.

Does PD Change Over Time?

A person's pupillary distance will change when they are physically growing. Once they reach maturity and stop growing, their pupillary distance will change very little. This means that adults can typically use the same PD measurement for a long time.