Free tool · runs in your browser
Measure Your Pupillary Distance Online
Get your PD from one front-facing photo, without a card or a printed ruler. The tool finds both irises, uses the iris itself as the ruler, and gives your distance PD, near PD and both monocular PDs in millimetres, drawn on your eyes.
Drop a photo, paste one, or choose a file
Straight-on, whole face visible, even light. JPG, PNG or WebP.
Runs in your browser. Your photo never leaves your device.
How it is measured
Your iris is the ruler.
A photo has no scale, which is why most online PD tools ask you to hold a bank card to your forehead. The visible iris is close to 11.7 mm across in most adults, so the tool measures both irises in pixels and converts the pupil-to-pupil distance to millimetres. Monocular values are split at the bridge of the nose, halfway between the inner eye corners, after head tilt is removed. Expect about ±2 mm: irises vary between people by a few percent.
- Distance PD
- Pupil centre to pupil centre, looking into the distance. The number most glasses orders ask for.
- Near PD
- About 3 mm less, for reading glasses: the eyes turn in to read.
- Monocular PD
- Each pupil to the bridge of the nose. Progressive and high-prescription lenses need these.
Measure it yourself
How to get the most accurate PD from a photo
- 1Hold the phone at eye level, about an arm's length away, or have someone take the photo.
- 2Look into the camera lens, not at the screen, with both eyes open and relaxed.
- 3Use even light from the front; avoid glasses, coloured contacts and strong shadows.
- 4Take two or three photos and compare: results within 1–2 mm of each other are a good sign.
Skip the ruler: the free tool above does it from one photo in about 30 seconds ↑
What's normal
Typical adult PD
- Adults
- Range: about 50–75 mm
- Note: average about 63 mm; almost all adults fall between 45 and 80 mm
- Near PD
- Range: distance PD − 3 mm
- Note: a common optician rule of thumb for reading distance
Sources
What this is based on.
The measurement and its reference ranges come from published research. Studies use different methods and populations, so compare your number with the range shown on this page rather than with other tools.
- 1.
Dodgson NA (2004). Variation and extrema of human interpupillary distance. Proceedings of SPIE 5291, Stereoscopic Displays and Virtual Reality Systems XI. doi:10.1117/12.529999
Interpupillary distance across adults: the average is about 63 mm and most adults fall between roughly 50 and 75 mm.
- 2.
Rüfer F, Schröder A, Erb C (2005). White-to-white corneal diameter: normal values in healthy humans obtained with the Orbscan II topography system. Cornea. PubMed 15778595
The visible corneal (white-to-white) diameter averaged 11.71 mm in healthy adults, which is why the iris works as a ruler.
Our own data: how much each reading moves when the same face is photographed again is published on the methodology page. How we choose sources.
Related tools
FAQ
What is pupillary distance?+
The distance between the centres of your pupils in millimetres. Lenses are cut so their optical centres sit in front of your pupils; if they are off, the lens acts like a weak prism.
How accurate is a PD from a photo?+
Usually within about 2 mm, because it relies on the iris being about 11.7 mm across. That is fine for most single-vision glasses. For progressives or strong prescriptions, have an optician confirm.
What if my two monocular PDs are different?+
That is normal: faces are not perfectly symmetric, and differences of 1–2 mm are common. Use both values if your order asks for them.
Why doesn't it need a card?+
The card is only a scale reference. Your iris does the same job, and it is already in the photo.
Is my photo uploaded?+
No. Everything runs in your browser.
One reading here.
Nineteen in the app.
A controlled scan, every reading against its ideal band, bone vs trainable, a plan, and a 3D model on Face ID iPhones.