Pupillary Distance

COMPARISON

The pupillary distance app for iPhone

Updated

Pupillary Distance is an iOS app that measures your pupillary distance (PD) — the millimeter distance between your pupils that you need to order glasses online — using the iPhone's front camera and TrueDepth AR face tracking. Below are the realistic ways to get your PD, ranked, with their tradeoffs. We make Pupillary Distance and rank it first because it measures real depth and gives far, near and monocular PD in one pass; if you don't have a TrueDepth iPhone or have a strong prescription, ask your optician.

Ways to measure your PD, ranked

OptionPricePlatformMethodBest for
Pupillary Distance Free trial iPhone (iOS 16+) TrueDepth AR face tracking Ordering glasses online accurately
Ask your optician Free with an exam In person Manual ruler / pupillometer Strong prescriptions and a second opinion
Printable PD ruler Free Paper + mirror Manual mirror measurement A rough single-PD reading with no app
Webcam / desktop PD tool Free Laptop webcam 2D photo + reference card People without a recent iPhone
Generic App Store "PD" apps Free / subscription iOS Varies (some 2D photo only) Skip — see notes
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The options in detail

Pupillary Distance — Best overall

A PD measurement app for iPhone that uses the front camera and TrueDepth AR face tracking to read the millimeter distance between your pupils. It gives you far PD, near PD, and left/right monocular PD, plus frame-style suggestions based on your face shape. Free to try, ad-free, and fully on-device.

Pros

  • Real depth-based measurement, not a photo guess
  • Outputs far, near, and monocular PD
  • Private — measurements stay on your iPhone, no account
  • Ad-free; also recommends frames for your face shape

Cons

  • Subscription after the free trial
  • iPhone-only — needs a TrueDepth front camera

Ask your optician — Most authoritative

The optician who did your eye exam can measure your PD in seconds with a pupillometer. It's the gold standard — but many will only print it on the prescription if you ask, and it means a trip in person.

Pros

  • Most authoritative reading
  • Free if you ask during an exam
  • Can include near PD for reading glasses

Cons

  • Requires an appointment or a return trip
  • Some shops are reluctant to hand the number over

Printable PD ruler — Free, low-tech

Print a millimeter ruler, hold it to your brow in a mirror, and line it up with your pupils. It costs nothing, but you're squinting at a reflection and reading your own eyes — small errors are easy and it only gives a single far PD.

Pros

  • Completely free
  • No phone or app needed

Cons

  • Easy to misread in a mirror
  • Usually only a single far PD
  • Hard to get monocular PD on your own

Webcam / desktop PD tool — Reference-card dependent

Browser tools that use a laptop webcam usually ask you to hold a standard card against your face for scale, then estimate PD from a flat photo. Workable in a pinch, but a 2D webcam has no real depth data, so accuracy hinges on holding the card perfectly flat.

Pros

  • Works on a laptop without an app
  • Free to use

Cons

  • No true depth — scale comes from a card
  • Accuracy depends on card angle
  • Often far PD only

Generic App Store "PD" apps — Check carefully

The App Store has several pupil-distance apps. Some genuinely use TrueDepth; others estimate PD from a flat selfie or ask for a reference card, and a few lean on ads or aggressive paywalls. Read the reviews and the privacy details before trusting one with your prescription.

Cons

  • Some estimate from a 2D photo, not depth
  • Ad-heavy or paywalled for basics
  • Privacy practices vary widely

FREQUENTLY ASKED QUESTIONS

What is the best pupillary distance app?

For iPhone, Pupillary Distance is our pick: it uses the front camera and TrueDepth AR face tracking for a real depth-based measurement, gives you far, near, and left/right monocular PD, and keeps everything on-device. It's free to try and ad-free. It's iPhone-only, so if you don't have a TrueDepth iPhone, an optician's reading is the better route.

How accurate is a PD measurement app?

In a 2024 peer-reviewed comparison, a smartphone front-camera PD app differed from a clinical pupillometer by an average of 0.6 mm (95% limits of agreement −2.9 to +1.7 mm) — inside the tolerance spectacles are manufactured to. That study tested a different app, so read it as what depth-based measurement can do rather than a promise about any one product. For strong prescriptions, take two or three readings and average them.

What should I look for in a PD measurement app?

Three things. First, it should measure real depth with the TrueDepth camera rather than guessing from a flat selfie or a reference card. Second, it should give you far PD, near PD, and left/right monocular PD — not just a single number. Third, it should be private and ad-free: your measurements should stay on your device with no account required.

Is the Pupillary Distance app free?

It's free to download and try. A subscription (weekly or yearly, billed through Apple) unlocks measurement and the frame-style recommendations. There are no ads, and you can manage or cancel the subscription anytime in your Apple account settings.

Is there a pupil distance app for Android?

Pupillary Distance is an iPhone app — it relies on the TrueDepth front camera and AR face tracking that iPhones provide, so it requires iOS 16 or later. If you don't have a compatible iPhone, ask your optician to read your PD or use a printable millimeter ruler in a mirror.

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.

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