PD Meter: Pupillary Distance

Ordering glasses online and need your PD? PD Meter helps you measure your pupillary distance (PD) in millimeters using a front-camera selfie and any standard-size card, like a credit card, for scale — no ruler, no second person, no trip to the optician.

Your pupillary distance is the gap between the centers of your pupils. Online eyewear stores ask for it so your lenses are centered correctly in the frame. PD Meter gives you a quick, repeatable estimate from the comfort of your home.

HOW IT WORKS

• Hold a standard card (a credit card, ID or any ISO-size card) under your eyes — its known width gives the app a real-world scale.
• Take a front-camera selfie, looking straight at the lens.
• Mark the center of each pupil and the edges of the card.
• PD Meter converts pixels to millimeters and shows your PD instantly.

WHAT YOU GET

• PD in millimeters, ready to enter at checkout.
• Single (binocular) PD, the value most retailers request.
• A clear, guided flow with on-screen tips for good lighting and head position.
• Re-measure as many times as you like and average your results for confidence.

WHO IT'S FOR

Anyone buying prescription or blue-light glasses online, parents checking a child's fit, or anyone who simply wants their PD on hand without booking an appointment.

A NOTE ON ACCURACY

PD Meter provides an estimate based on your photo and the card scale. Results depend on lighting, camera angle and how precisely you place the markers. For high prescriptions or progressive lenses, confirm your PD with an optician. This app is not a medical device.

Recent changes:
Rewritten instructions: pupils first, then the two card ends, nose bridge optional. The point prompt now counts 1/4 to 4/4 and explains press, drag, let go.