How to Measure Your Pupillary Distance (PD) at Home
A 60-second guide to measuring your PD with a ruler and a mirror — accurate enough for most prescriptions.
Pupillary Distance (PD) is the millimeter distance between the centers of your pupils. Measure it by holding a millimeter ruler across the bridge of your nose, aligning 0 mm with one pupil, and reading the number that lines up with the other pupil. Most adults are between 54 and 74 mm.
Grab a millimeter ruler and a mirror
Use a ruler with millimeter (mm) markings — most basic rulers have them. Stand in front of a mirror, far enough away that you can see your eyes clearly. Good lighting helps.
Close your right eye
Hold the ruler horizontally across the bridge of your nose, level with your eyes. Align the 0 mm mark with the center of your left pupil (the eye that's still open).
Switch eyes — open right, close left
Without moving the ruler, open your right eye and close your left. Read the millimeter mark that lines up with the center of your right pupil. That number is your PD.
For most adults, PD is between 54 mm and 74 mm. Typical women: 56–62 mm. Typical men: 60–68 mm.
Repeat 3 times for accuracy
Measure twice more and use the average. If your three readings differ by more than 2 mm, ask a friend to help — it's hard to keep the ruler perfectly steady on yourself.
Enter the PD at LensTrove checkout
When you check out, you'll see a PD field for both Single Vision and Progressive lenses. Enter your PD as a single number (e.g. 62). LensTrove will use it to center the lenses correctly in your frame.
FAQ
What is PD and why do I need it?
PD stands for Pupillary Distance — the distance in millimeters between the centers of your pupils. It's used to position the optical center of each lens directly in front of each pupil. Without an accurate PD, your lenses won't be aligned with your eyes, which can cause eye strain, headaches, and blurry vision in prescription glasses.
Is PD usually on my prescription?
Sometimes, but often not. US optometrists are not legally required to include PD on a written prescription. If yours doesn't have a PD value, you'll need to measure it yourself or ask the optometrist to add it.
What is a typical PD value?
Most adults are between 54 and 74 mm. Average for women is around 60 mm; average for men is around 64 mm. Children average 41–55 mm.
What if I have two PD numbers (like 32 / 30)?
That's a 'dual PD' or 'monocular PD' — the distance from the bridge of your nose to each pupil separately. The two numbers added together equal your total PD. Most lens orders use the total PD; LensTrove accepts either format.
What is the difference between distance PD and near PD?
Distance PD is for looking at objects far away (driving, watching TV). Near PD is slightly smaller — usually 2–3 mm less — for reading. Single-vision distance lenses use distance PD. Progressive lenses use distance PD plus a near-vision adjustment built into the lens design.
Can I measure PD with my phone?
Some apps claim to measure PD using your phone camera, but accuracy varies. The ruler-and-mirror method takes 60 seconds and is reliably within 1–2 mm of an optician's measurement. We recommend the manual method.
What happens if I enter a slightly wrong PD?
A 1–2 mm error usually goes unnoticed for low-prescription single-vision lenses. Higher prescriptions (above ±3.00 D) are more sensitive — a 3+ mm error can cause headaches and eye strain. If you're unsure, measure 3 times and take the average, or have a friend help.
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