Measure your pupillary distance at home with a printed or on-screen ruler, and convert between single (binocular) and dual (monocular) PD. No camera, no signup, no email.
| Value | mm | Used for |
|---|
The bar below must measure exactly 85.60 mm (the short edge of a bank card). If it is longer or shorter, your printer scaled the page — reprint at 100% / "Actual size".
0 = centre of your right pupil while looking straight ahead. Read where your left pupil centre falls, that number is your single PD.
Tip: stand about 20 cm from a mirror, hold the ruler against your brow, close your right eye to line the 0 mark up with your left pupil, then close your left eye and read the mark at your right pupil.
No printer? Calibrate the ruler below with a bank card, then hold a ruler-free measurement against the screen — or use your phone: hold the phone at the same distance as your glasses and compare.
Accuracy: expect ±1 mm with care. For strong prescriptions, high cylinders, prism, or progressive lenses, a measured PD from your optician is better than a home measurement — it is one of the few numbers that directly changes how the lens sits in front of your eye.
| Group | Typical single PD | Notes |
|---|---|---|
| Adults — average | 63 mm | Most adults land between 58 and 68 mm |
| Adults — full range | 54–74 mm | The range quoted across optometry references |
| Adult men | 62–67 mm | Typically 1–2 mm larger than women on average |
| Adult women | 60–65 mm | Average around 62 mm |
| Children, about 5 years | ~50 mm | Child PD grows quickly: roughly 1 mm per year between 5 and 8, then slower. Always measure rather than assume for a child's glasses. |
| Children, 6–9 years | ~52–56 mm | |
| Children, 10–13 years | ~56–60 mm | |
| Teens, 14+ | ~60–63 mm |
The optical centre of a lens is the only point where the lens does exactly what your prescription says. Lenses are positioned so that your pupils sit at — or very near — that point. Get the PD wrong by a few millimetres and you introduce unwanted prism, which can cause eye strain, headaches and a "swimmy" feeling, especially in strong prescriptions.
PD also interacts with the frame you choose: a frame whose eyesize and bridge put its optical centres far from your pupils forces the lab to decenter the lenses, which makes the edges thicker. Check that in the frame size calculator, and see the effect on thickness in the lens thickness calculator.
Reading or "near" PD is about 3 mm smaller than your distance PD (1.5 mm per eye for dual PD), because your eyes converge when you look at something close. Progressive and reading lenses are usually made with a near PD.
Look for a two-digit number near the lens powers, often labelled PD, or two numbers written as a pair (for example 31.5/31.5) which is a dual PD. It is often absent: many optometrists only record it for the lenses they dispense, so you may have to ask for it or measure it yourself.
With the printed ruler and a mirror you can get within about 1–2 mm with care, which is fine for low and moderate prescriptions. If your prescription is above roughly ±4.00 D, has a large cylinder, includes prism, or you are ordering progressives, it is worth asking your optician for a measured PD — a home measurement is not a fitting.
In adults it is essentially stable. In children it grows with the face — roughly 1 mm per year between ages 5 and 8, slowing after that — so children's glasses should be measured fresh each time.
Yes. Your distance PD is measured looking at something far away; when you read, your eyes converge, so a near PD about 3 mm smaller (1.5 mm per eye) is used for reading and progressive lenses. That is a calculation your optician or lab does — you only need to supply your distance PD.
Then a dual PD is the more accurate input: each eye is placed on its own optical centre instead of both being placed by a single average. It matters most for strong prescriptions and for anyone whose eyes sit noticeably off-centre. Enter both values above to see the total.
No. All of our measuring tools are optical geometry on your inputs or a ruler you calibrate yourself — nothing uses your camera, and we do not want a photograph of your face.
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Not medical advice. This page provides measuring tools and arithmetic, not a fitting. It does not measure, diagnose or correct vision. For strong prescriptions, prism, progressives or children, have your PD measured by your optician.
LensCrunch — optical tools for people who care about the maths.