Measure pupillary distance online
Get a photo-based estimate of the distance between your pupils, with separate left and right readings and the iris scale used to calculate it.
Measure pupillary distance online workspace
Use a sharp, level photo with both eyes open and looking toward the lens. The calculation happens on your device and returns an estimate rather than a lens-ordering measurement.
Millimetres here depend on an assumed iris size. This photo has no personal physical calibration. Have a dispensing professional confirm the values needed for glasses.
Meet your face, in a new way.
Drop a photo here or choose a portrait from your device.
JPG, PNG, WebP or HEIC/HEIF · up to 30 MB · at least 320 × 320 pxA good photo makes the difference
- Look straight at the camera, with your head level.
- Use even daylight, without strong side shadows.
- Keep your face visible. Remove glasses and avoid filters.
- Use a recent photo with just one face and a neutral expression.
Measurements describe this photo. Camera distance, expression and lighting can change the result. They are not a medical assessment or a measure of your worth.
Your photo is prepared locally as JPEG, and the free scan runs in this browser. The scanner loads its engine from this site; your photo is not sent to us or any third party. A complete report uploads the same prepared photo only after your separate consent.
- We store
- If you are signed in, a usage count: which tool and step, never results or measurements.
- We never store
- Your photo, face points or results; the scan runs in this browser.
- How long
- The photo is cleared when you leave the page. Numbers you choose to save stay in this browser until you clear them. Privacy policy
Your portrait is processed in this browser for the free calculation. The optional report asks separately for upload permission and shows its price before purchase.
What does it mean to measure pupillary distance online?
Pupillary distance (PD) is the space between your pupil centres in millimetres. To measure pupillary distance online from one photo, a tool needs a known size in the picture. This one uses the average size of the iris instead of a card.
A PD measurement is a length, not a rating
A wider or narrower PD is not better. It is a fitting number for glasses, separate from symmetry or attractiveness.
Check your face symmetryHow photo conditions affect the way you measure pupillary distance
Looking at something close makes the eyes converge. Camera height, glare, contact lenses, blur and half-closed lids can also shift what the detector sees.
Check your pose in the true mirrorA glasses form may ask for one number or for two. Read the labels rather than guessing from the number of fields. Binocular PD is a combined pupil-to-pupil measurement. Monocular PD describes each eye separately relative to a fitting reference. Near PD concerns closer viewing. The photo-axis values and near-use conversion here have narrower meanings.
Your right and left values can differ because the detected centre line need not sit halfway between the pupils. We calculate each side separately instead of dividing the total by two. The fitted photo axis is not a measured optical bridge position, so these figures should not be relabelled as an optician's monocular PDs.
The near-use field subtracts 3 mm from the displayed photo total, following a common retail conversion. It does not observe your eyes at a specific reading distance. Do not confuse that arithmetic with a second measurement, or assume the original photo already represents distant fixation. Ask the person dispensing your lenses which values their order requires.
Why measure pupillary distance online with this tool?
You see exactly how the millimetres were calculated, and you can measure pupillary distance online without printing anything or holding a card. The result also shows a near-use value and how much the iris assumption could shift it.
A pupillary distance calculator that needs no card
The iris is about 11.7 mm across in most adults (±0.5 mm, per Google's MediaPipe Iris notes). Your measured iris pixels set the scale, so the result is an estimate with that uncertainty.
Photo estimate = projected pupil pixels ÷ mean iris-diameter pixels × 11.7 mmPrint an actual-size PD rulerMeasure PD online for each eye
Right and left values are measured separately from the face centre line rather than splitting the total in half, because your pupils need not sit evenly around it.
Pick frames for your faceThe local detector supplies 478 face and iris landmarks. We use the centres of the two iris groups and opposing points on their rings. After converting both image axes to pixels, the average ring diameter becomes the ruler. The calculation assumes an iris reference of 11.7 mm; it does not know your personal iris diameter.
Google's MediaPipe Iris documentation describes horizontal iris diameter as roughly 11.7 ± 0.5 mm across a broad population. That is a useful prior rather than an exact constant in every adult. A wider assumed iris makes every millimetre estimate larger. The two reference scenarios in your result make that dependence visible without presenting a clinical error bound.
Both iris spans need at least six pixels, an open visible eye and usable landmarks. The two spans must not differ by more than twenty per cent of their mean; those direct eye checks can still request another photo. A four-point depth reference is shown only when it has enough source pixels. Missing depth or values outside the preferred ±10° yaw and −25° to 18° pitch range produce a caution rather than pretending that the reference is zero. These rules do not establish prescription accuracy or a personal physical scale.
Landmark and axis details
The unmirrored person's right iris uses centre 468 and ring points 469/471; the left uses centre 473 and 474/476. Five central face points fit the forehead-to-chin axis. We measure the pupil span and both side distances perpendicular to that axis. Cheek points 234/454 supply the visible face-width estimate using the same assumed scale.
These methods share a goal but use different information. When you measure pupillary distance online here, no card is needed because it borrows a population iris reference. A card-based tool can use a known physical size, provided that the reference is correctly sized and positioned. An optician can measure with the fixation and fitting conditions needed for the lenses.
A card can connect image pixels to a real-world length. Its position, angle and distance from the eyes still matter, and a credit-card-sized object should be checked rather than assumed. Adding a card to a photo does not automatically make an unvalidated algorithm clinically accurate.
Optical retailers explain that PD helps position lenses and that an error matters more with stronger prescriptions. A professional can clarify distance versus near values and separate right and left measurements. Our calculator does not choose a prescription, verify frame fit or promise a millimetre tolerance. Paying for the styling report does not change that boundary.
How to use it in 3 steps
Prepare the eye area
Use an adult portrait with the camera at eye level, head square and eyes open. Even light and no glasses or glare give the clearest iris edges.
Line up in the online mirrorCheck the PD calculator's ruler on your eyes
Run the scan and look at the centre dots and green iris lines before reading the millimetres. If a line crosses an eyelid or a reflection, retake the photo.
Find your eye shapeKeep the estimate in context
Compare the two reference-size scenarios to see how much the assumed iris size matters, and save a labelled PNG. For strong prescriptions, confirm with an optician.
Find your face shape
After you measure pupillary distance online, try other photo measurements: Face shape · Eye-corner tilt · Facial symmetry
Measure pupillary distance online: FAQ
How to measure pupillary distance?
Upload a straight-on photo here to measure pupillary distance online, use a ruler in front of a mirror, or ask an optician, which is the most precise option.
What is pupillary distance?
Pupillary distance (PD) is the distance between the centres of your pupils in millimetres. Glasses use it to centre each lens in front of your eye.
What is pupillary distance in a prescription glasses?
It is the PD value on your prescription, often marked PD as one number or two (right and left). Some prescriptions leave it out; ask your optician for it.
What is the average pupillary distance?
Adult PD is commonly around 54–74 mm, often a little lower for women than men. Your own value matters more than the average.
Does pupillary distance change?
It grows through childhood and stays fairly stable in adults. Near PD is smaller than distance PD because your eyes turn inward to read.
Does pupillary distance matter?
Yes. A wrong PD shifts the lens centres and can cause eye strain, especially with stronger prescriptions or progressive lenses.
How to measure pupillary distance at home?
Stand at arm's length from a mirror, hold a millimetre ruler under your eyes and read from one pupil centre to the other, or ask someone to help.
How to measure pupillary distance online?
Upload a clear front photo to this tool. It finds both irises, uses their average size as a ruler and returns a total and per-eye estimate.
Do I use distance or near PD when ordering glasses?
Use distance PD for everyday glasses and near PD for reading-only glasses. Our near value subtracts 3 mm, a common retail conversion.
Do you need pupillary distance for contacts?
No. Contact lenses sit on the eye, so they do not need PD. Prescription sunglasses and glasses do.
Can I measure pupillary distance online with a credit card?
Some tools use a card as a size reference. This one does not need a card; it uses the average iris size, so treat the result as an estimate.
Is it free to measure pupillary distance online here?
Yes. The scan, both side readings and the PNG download are free; only the optional full face report is paid.
Is there a printable ruler to measure pupillary distance?
Yes. Our printable PD ruler prints at actual size with a calibration check, for measuring with a mirror or a helper.
How does a photo get a millimetre scale without a card?
It assumes an average iris diameter of 11.7 mm and divides your pupil distance by the measured iris width in pixels. Unusual iris size adds error.
Does this PD tool upload my photo?
No. Iris detection runs in your browser and the free result stays on your device. A paid report asks for separate consent before any upload.