Cortel Designs

PD Finder

How to Measure Pupillary Distance at Home

If you need to measure PD at home, this free tool gives you your pupillary distance in millimeters from a simple selfie. Take off your glasses, hold any credit, bank, or gift card (they're all 85.6 mm wide) flat under your nose, look straight at the camera from about an arm's length (15–18 inches), tap the card edges and your pupils, and get your PD instantly. The card gives us the scale, and your photo stays on your device unless you choose to send it to Cortel Designs.

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Studio portrait of a man wearing eyewear fitted with loupes

1. Get your photo

Hold a credit card flat against your face, just under your nose, look straight at the camera, and hold the camera about 15–18 inches (38–46 cm) from your face.

Example selfie: person without glasses holding a credit card under the nose, eyes clearly visible

Take your glasses off first

Your pupils need to be clearly visible — lenses and frames throw the measurement off.

Your selfie should look like this: no glasses, credit card under your nose, eyes clearly visible, looking straight at the camera from 15–18 inches away.

How to measure pupillary distance with PD Finder

The easiest way to measure PD at home is to use a standard-size card as a built-in ruler. Here's how:

  1. Take your glasses off, hold a credit card flat against your face under your nose, look straight at the camera, and take your selfie from about 15–18 inches (38–46 cm) away.
  2. Tap the left and right edges of the credit card — that's the 85.6 mm scale.
  3. Tap the center of each pupil. Drag any dot to fine-tune; a magnifier helps you aim.
  4. We compare the distance between your pupils to the card width to get your PD in millimeters.

This is an estimate for your convenience, not a medical measurement. For prescription eyewear, confirm your PD with your optician.

Common questions about how to measure pupillary distance

How do I measure pupillary distance at home?
To measure PD at home, take a straight-on selfie with a credit card held flat under your nose — look straight at the camera from about 15–18 inches (38–46 cm) away — then tap the left and right edges of the card and the center of each pupil. PD Finder uses the card's known 85.6 mm width as a scale and calculates your pupillary distance in millimeters.
What is pupillary distance?
Pupillary distance (PD) is the distance between the centers of your pupils, measured in millimeters. It's used to position the lenses correctly when you order glasses or loupes.
Can I measure PD at home without a ruler?
Yes. Any credit card, bank card, or gift card works as the ruler — they all share the same standard width of 85.6 mm, so the tool can calculate your PD from the photo.
Is my photo uploaded anywhere?
No. All measuring happens on your phone or computer, and your photo never leaves your device.
Is this accurate enough for glasses or loupes?
The tool gives a careful estimate for your convenience, not a medical measurement. For prescription eyewear, confirm your PD with your optician.