Free tool
Measure your PD
Your pupillary distance is the gap between the centres of your pupils in millimetres. Lenses are centred on it, so it matters. Three ways to get it, none of them need an optician.
Look straight at the camera and hold still for a few seconds. We take the median of 30 steady frames.
Nothing is recorded or uploaded.
Works on phones and laptops with a front camera. On iPhone use Safari.
A straight-on selfie, glasses off, eyes open, even light. The photo stays on your device.
Stand at a mirror
About 20 cm away, face level, glasses off. Or ask a friend to read the ruler for you.
Rest the ruler on your brow
Hold a millimetre ruler flat against your eyebrows, numbers facing the mirror.
Close your right eye
Line the zero up with the centre of your left pupil. Keep your head still.
Close your left eye
Read the millimetre mark over the centre of your right pupil. That is your PD.
Repeat three times
Take the number you got most often. Adults usually land between 54 and 74 mm.
Reading glasses?
Subtract 3 mm for a near PD. Single-vision distance glasses use the number as read.
On-screen ruler
Screens differ, so calibrate first: hold any bank card against the outline and move the slider until the card fits exactly. The ruler below then reads in true millimetres. Hold your phone against the mirror to read it, or print it.
Bank card goes here