Measuring your pupillary distance
All you need is a ruler, a mirror and a few minutes.
Pupillary distance (PD) is the space between the centres of your pupils, in millimetres. It shows where the centre of each lens should sit, so you look through the right part of the lens.
Check your prescription first
Your PD may already be on your prescription. If it is not, ask the clinic that wrote it. That number is more exact than one you measure yourself.
Measure it at home
- Stand about 20 centimetres from a mirror, in good light.
- Hold a millimetre ruler flat against your brow and keep it level.
- Close your right eye. Line up the zero with the centre of your left pupil.
- Keep the ruler still. Close your left eye and open your right eye.
- Read the number at the centre of your right pupil. That is your PD.
- Repeat three times and use the average.
A friend can also measure for you. Look straight ahead at something about 3 metres away while they hold the ruler.
Reading the result
- Most adults measure between 54 and 74 millimetres. Kids measure less.
- A PD can be written as one number, such as 63, or as two, such as 31/32. Two numbers give the distance from your nose to each eye. Send us the numbers as written.
Before you order
A home measurement is less exact than one from an optometrist or optician. For progressive lenses or a strong prescription, ask a professional to take it.
When you have your number, send it with your prescription. Our prescription lenses page explains the steps.