Free PD tool · runs on your device
Measure your pupillary distance.
No optician required.
Pupillary distance (PD) is the millimeters between the centers of your two pupils. Every online glasses retailer asks for it. Most opticians won't give it to you. Your camera + any wallet-size card can.
We'll watch your eyes through your camera. Nothing leaves this browser — no frames are uploaded or saved.
What is PD?
PD is the distance between the centers of your pupils, in millimeters. Glasses lenses have an optical center; that center has to line up with your pupil for the prescription to work as intended. Wrong PD = lenses that pull your eyes off-center, headaches, eyestrain, and a vague sense that the glasses "don't feel right."
Adults typically measure 54–74 mm. Children, lower. Most online retailers default to 63 mm — fine for many people, wrong for plenty. Knowing your number means your glasses get made for your face.
How this measures it
A standard ISO/IEC 7810 ID-1 card — credit card, driver's licence, most national IDs — is exactly 85.6 mm wide (ISO/IEC 7810). Hold it flat against your forehead and we capture a snapshot. The card and your eyes are now in the same plane, so the pixel width of the card sets the scale. Your iris-to-iris pixel distance, divided by that scale, gives your PD in millimeters.
Iris detection is via Google's MediaPipe Face Landmarker, running locally in your browser. No video frames are uploaded or stored.
Want to know more about your eyes? The free Eyeball Analyzer walks you through why your eyes got worse, your personal numbers, and what actually fixes it — about 20 minutes.
Limitations & disclaimer
EndMyopia treats myopia as a refractive state, not a medical condition. This is a free educational tool — not medical advice, diagnosis, or a substitute for a licensed optometrist. Measurements depend on camera quality and how carefully you mark the card edges; expect ±5–10 % on laptops, ±10–15 % on phones. For lens orders, eye health concerns, or any task requiring full 20/20 vision, see a licensed professional.