Tools / Health & family
Pupillary distance
Buying glasses online and they ask for your PD? Take a selfie holding a card (ID or bank card) under your nose: the tool finds your pupils and measures the distance between them in millimetres, with each eye separately. Runs on your device; the photo never leaves it.
Your file never leaves your device — everything runs in your browser
How to use it
- Hold a bank-card-sized card horizontally under your nose, touching your face; look straight at the camera and shoot from arm's length.
- Drag the two handles to the card's edges in the photo — that's the scale (85.6 mm).
- Read the total PD and each eye's, and compare with the approximate reading from iris size.
Questions
How accurate is it?
With the card against the face and a straight gaze, usually within ±1 mm. Without a card we use the iris diameter (≈11.7 mm for most people), so ±2 mm. An optician is more precise; for strong lenses, use their measurement.
Why each eye separately?
Some noses are not exactly centred, and sites ask for a «monocular PD» per eye. We measure from the bridge of the nose to each pupil.
Near or distance PD?
Looking at the camera at arm's length gives close to the distance PD. Near PD (for reading) is about 3 mm less.
Is the photo stored?
No. It is processed in your browser and gone when you close the page.
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