What is pupillary distance?

Pupillary distance (PD) is the measurement in millimetres between the centres of your pupils. It is used by opticians to align the optical centres of spectacle lenses with your eyes, ensuring clear and comfortable vision. Average PD is 62–64 mm for adults.

Measurement technique

This tool uses a credit card (ISO standard width 85.6 mm) as a scale reference. By marking the card edges and pupil centres in a captured photo, the tool calculates pixel-per-mm scale and derives the PD.

Disclaimer

This is an informational estimate only. Do not use this measurement as a substitute for a clinical PD measurement by a registered optician before ordering prescription eyewear.

Monocular vs. binocular PD

Binocular PD (total PD) is the distance between both pupils and is used for single-vision lenses. Monocular PD measures each pupil separately from the center of the nose bridge (e.g., 32/30 mm for right/left). Monocular PD is required for progressive lenses and bifocals, where the optical centers must be independently aligned for near and distance zones. Many online eyeglass orders request both values.

Standard PD ranges

Adult female: average PD 58–64 mm
Adult male: average PD 62–68 mm
Children (ages 4–14): typically 44–58 mm

Values outside your gender/age range are normal — PD is highly individual.

When to see an optician

Professional PD measurement is especially important for:

Prescriptions above ±4.00 diopters (high power; small PD errors cause significant prismatic effect)
Any prescription containing prism correction
Progressive or multifocal lenses (monocular PD required)

Errors in PD can cause eyestrain, headaches, and visual fatigue — consult an optician if in doubt.