PD Meter: Pupillary Distance

Estimate your pupillary distance with PD Meter using a front-camera selfie and a standard 85.6 mm card. Mark the photo yourself to see an approximate PD in millimeters, then review what the number means before discussing glasses measurements with an optician.

HOW THE PHOTO MEASUREMENT WORKS
Rest a bank card or credit-card-sized ID flat against your cheekbones, just below the eyes. If your nose tilts the card, place it flat on your forehead instead. Keep its long edge level, face the camera in even light and look straight into the lens. Choose the capture distance that matches your setup: about 30 cm or arm's length, about 60 cm.

Take the selfie and mark four points: the center of each pupil and the two ends of the card's long edge. The known card width provides the scale. A magnifier and adjustable markers help you review placement; you can re-mark the card or pupils without taking another photo. This is a manual photo method, so the result depends on your markings.

UNDERSTAND YOUR PD
• Distance PD is the estimated gap between your pupils, with a model-based correction for capture distance and card depth.
• Add a nose-bridge marker for separate right and left PD values. Without that marker, the two halves are an even-split estimate.
• Near PD is calculated as distance PD minus 3 mm; it is an estimate, not a separate reading measurement.
• A VR headset may call distance PD “IPD”. Confirm the headset's own fitting instructions before using the value.

REVIEW REPEATED READINGS
The history keeps up to 20 measurements and shows a filtered average of current-model readings. Save a person's result under a name or share the PD text when you need a reference. Repeating a photo in a similar position helps reveal inconsistent markings; averaging does not guarantee accuracy.

LIMITS AND COMMON QUESTIONS
Do I need a card? Yes. Use the 85.6 mm long edge of a standard card, not an arbitrary object or the short edge. Is this automatic eye detection? No: you place and adjust the points. Why might results vary? Lighting, head angle, card tilt, capture distance and marker position all affect the estimate. The app flags values outside its 50–80 mm plausibility window; that flag is a prompt to review the photo, not a diagnosis.

Camera permission is needed to take the selfie. The app contains advertising and uses Firebase Analytics and network-based ad configuration. For prescription eyewear, especially progressive lenses, confirm measurements with an eye-care professional rather than relying on a phone estimate alone.

This app is not a medical device and does not diagnose, treat, cure or prevent any medical condition. Consult a healthcare professional for medical advice, diagnosis or treatment.

Recent changes:
PD Meter now checks the second card mark as you place it: a mark on top of the first one, or one too short or too wide for the card's long edge, is not placed, and a dotted circle shows where the other end probably is. Two marks on the same eye are caught too. After "Measure 2 more times", Your PD, Share and Saved People use the middle of your 3 reads, and a read far from the others can be re-measured on its own.