Pupillary Distance

iPhone · TrueDepth

Know your PD before you buy glasses.

Pupillary Distance is an iOS app that measures your pupillary distance (PD) using the iPhone's front camera and TrueDepth AR face tracking, so you can order glasses online accurately. It also recommends eyeglass frames based on your face shape. It's free to try, ad-free, and private — measurements never leave your device.

The pupillary distance app for iPhone. Measure your PD with the front camera — accurate to the millimeter — then order glasses online with confidence. Free to try, ad-free.

Download the App Measure PD online
PD measurementSample reading
Person measuring their pupillary distance with the iPhone front camera
Far PD
63.5mm
Near PD
60.5mm
Right eye
32.0mm
Left eye
31.5mm

Most adults fall between 54 and 74 mm. Yours is a number, not a guess.

FEATURES

Everything you need before you order glasses.

Front-camera PD

Your iPhone's TrueDepth camera maps your face in 3D and measures the distance between your pupils — no ruler, no mirror, no optician visit.

Far and near PD

Get your distance PD for everyday glasses and your near PD for reading, plus separate left and right monocular values.

Frame finder

Answer three quick questions about your face shape and get eyeglass frame styles that actually suit you.

  • 4.4★App Store rating
  • 10languages supported
  • 100%on-device — nothing uploaded

HOW IT WORKS

What the app does

Person holding an iPhone at arm's length while the app measures the distance between their pupils

Measure your pupillary distance with your phone camera. Fast, simple, and made for ordering glasses online.

Check your vision in seconds with quick visual acuity and color vision tests.

A color vision test plate beside multiple-choice answers, as shown in the app

Save your eye prescriptions in one place. Scan, organize, and access them whenever you need.

Two scanned optometrist prescription forms saved side by side

Protect your eyes with smart 20-20-20 reminders. Take regular breaks and reduce screen strain.

A 20-20-20 reminder showing every 20 minutes, 20 seconds, 20 feet

TESTIMONIAL

  • "I ordered glasses online for years guessing my PD. One scan and I finally had the exact number — my new lenses actually line up with my eyes now."

    Avatar of Lena Hoffmann

    Lena Hoffmann

    Ordered glasses online

FREQUENTLY ASKED QUESTIONS

What is pupillary distance (PD)?

Pupillary distance is the distance in millimeters between the centers of your two pupils. Opticians use it to center each lens in front of your eyes, which is why you need it to order glasses online.

How does the app measure my PD?

Pupillary Distance uses the iPhone's front camera and TrueDepth AR to map your face in 3D and measure the distance between your pupils — no ruler, mirror, or optician visit required.

How accurate is measuring PD with an iPhone?

Depth-based measurement is close to a clinical reading: in a 2024 peer-reviewed comparison, a smartphone front-camera PD app differed from an optician's pupillometer by an average of 0.6 mm, which the authors found small enough to stay within spectacle-manufacturing tolerance. For a strong prescription, take two or three readings and use the average.

Which iPhones does the app work on?

Any iPhone running iOS 16 or later. iPhones with a TrueDepth (Face ID) camera give the most precise depth-based reading.

Is my PD private?

Yes. Every measurement is stored locally on your device. There is no account and no server — nothing about your face or your PD is ever uploaded.

What's the difference between far PD and near PD?

Far PD is for glasses you look through at a distance; near PD is slightly smaller and used for reading glasses, because your eyes converge when you focus up close. The app gives you both, plus left and right monocular PD.

PREFER TO MEASURE BY HAND?

Two free ways to get your PD without the app

Our step-by-step guide on how to measure pupillary distance for glasses at home covers the ruler-and-mirror method, the friend method and the iPhone method, with the accuracy you can expect from each. If you only need a millimeter scale, the printable PD ruler prints at true size with a calibration bar so you can check your printer did not scale it.

BLOG

One eyeglass lens held to the light with a degree arc beside a short flat measurement span

Is Pupillary Distance the Same as Axis?

Is pupillary distance the same as axis? No — PD is in millimeters, axis in degrees. Why the two get confused on a prescription, and what a mix-up does.

Front-on view of glasses on a face with the frame width and the bridge width marked

How to Measure Your Face for Glasses (Frame Width, Bridge & Lens Size)

Measure your face for glasses: the three numbers on every frame, taking them from an old pair or your face, which one decides the fit, and where PD fits.

4.4★ · 310+ Reviews

Your PD, measured in under a minute.

Pupillary Distance turns your iPhone into an accurate PD meter. Measure once, then order glasses online with confidence.

Download the App