How to Measure Your Pupillary Distance
Learn how to measure your pupillary distance (PD) at home with ease. Understanding your PD ensures your lenses align perfectly with your eyes for optimal vision and comfort.
What is PD?
Pupillary distance (PD) measures the space between the centres of your pupils. Knowing your PD helps ensure your lenses align correctly with your eyes for clear, comfortable vision. Most adult PD values fall between 57–72 mm and are listed on your prescription.
How to measure PD with a friend
• Remove your glasses and gaze at a distant object to keep your eyes steady.
• Ask a helper to place a millimetre ruler against your brow with the 0 mm mark centred on your right pupil.
• Without shifting your gaze, have them note the measurement that lines up with the centre of your left pupil.
• Record this number in millimetres and repeat a couple of times to confirm accuracy.
Frequently Asked Questions
What's the difference between single PD and dual PD?
Single PD is one measurement across both eyes—it's the distance between the centres of your pupils. Dual PD provides two measurements: one from the bridge of your nose to each pupil. Dual PD is more precise and often used for progressive lenses or multifocal prescriptions, while single PD is common for standard single-vision glasses.