Pupillary distance, explained
Plain-English guides to measuring your PD and ordering glasses with confidence — no jargon, no hype.
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How to Measure Your Pupillary Distance (PD): A Complete Guide
Learn what pupillary distance (PD) is, why it matters for your glasses, and how to measure it accurately at home — with a ruler, a card, or your phone's camera. Includes common mistakes and how to check your result.
Read guide → How to Measure IPD for VR (With Your Camera, Free)
Your IPD is the one setting that makes VR sharp instead of blurry. Measure it in seconds with your camera — no ruler, nothing installed — plus where to set it on each headset.
Read guide →VR Headset IPD Ranges: 10 Headsets Compared (2026)
Quest 3, Quest 3S, Vision Pro, Valve Index, PSVR2, Pico 4 and more — the exact IPD range for 10 major VR headsets in one table, plus what to do if your number sits near the edge.
Read guide →How to Measure Your Child's Pupillary Distance (PD)
Ordering glasses for your child online? Here's how to measure a child's pupillary distance at home, typical PD ranges by age, and when to rely on the eye doctor.
Read guide →Single PD vs Dual PD: Which Do You Need? (+ How to Convert)
One number or two? Here's the difference between single and dual PD, which one your glasses order needs, and how to convert between them in seconds.
Read guide →Near PD for Reading Glasses: What It Is and How to Calculate It
Reading glasses use a 'near PD' that's slightly smaller than your distance PD. Here's why, how to calculate it from your distance PD, and when it matters.
Read guide →What Is the Average Pupillary Distance? PD Ranges by Age and Gender
What's a normal pupillary distance? See typical PD ranges for adults and children, how PD differs between men and women, and how to tell whether your measurement is reasonable.
Read guide →Why Every Site Gives a Different 'Normal' PD Range (54–74? 48–73? 55–65?)
One site says normal PD is 54–74 mm, another says 48–73, another 55–65. They're not contradicting each other — they're measuring different populations. Here's what the research actually shows, and how to tell if your number is normal.
Read guide →Does Pupillary Distance Need to Be Exact?
How precise does your PD really need to be? Here's how much error is tolerable, why it depends on your prescription, and when a millimeter matters.
Read guide →Exactly How Much Does a PD Error Matter? A Table by Prescription Strength
'Your PD should be close' — but how close? Using the optical formula that labs actually use, here's a table showing exactly how much a 1, 2, 3, or 5 mm PD error affects your vision at every prescription strength.
Read guide →Signs Your PD Might Be Wrong (and What to Do About It)
Eye strain, headaches, or blurry vision with new glasses can be a sign of an incorrect pupillary distance. Here's how to tell, and what to do next.
Read guide →What Happens If Your PD Is Wrong?
An incorrect pupillary distance can cause eye strain and headaches — but how much error actually matters depends on your prescription. Here's the real picture.
Read guide →How to Get Your PD from Old Glasses (Marker Method)
You can't read your PD off your glasses — but you can measure it from a pair you own in 3 steps. Here's the marker method, how accurate it is, and when to trust it.
Read guide →Does PD Matter More for Progressive Lenses?
PD accuracy matters for every pair of glasses, but for progressives it matters a lot more. Here's why, and what to measure.
Read guide →Can You Order Glasses Without Your PD?
No PD on your prescription? Here's how to get your pupillary distance — measure it yourself, ask your optician, or find it on record — so you can order glasses online.
Read guide →If Your PD Is Wrong, What Does Each Online Store Do? A Comparison
Ordered glasses online and the PD was off? Whether you get a free remake, store credit, or nothing depends on the retailer — and on whose mistake it was. A verified comparison of Zenni, Warby Parker, EyeBuyDirect and GlassesUSA.
Read guide →How to Find Your PD for a Zenni Optical Order (No Eye Exam Required)
Zenni asks for your pupillary distance at checkout, in single or dual format. Here's exactly what Zenni accepts, where to find your number, and what happens if it's wrong.
Read guide →Warby Parker PD: How to Find It (and What If It's Wrong)
Warby Parker asks for your PD at checkout. What format they accept, how their card-and-app tools work, and exactly what Warby Parker does if your PD turns out wrong.
Read guide →How to Find Your PD for a GlassesUSA Order
GlassesUSA needs your pupillary distance to make your lenses. Here's what GlassesUSA accepts, the ranges they cite, and how to get your number.
Read guide →How to Find Your PD for an EyeBuyDirect Order
EyeBuyDirect needs your pupillary distance to make your glasses. Here's what EyeBuyDirect accepts, how their built-in tool works, and how they handle a wrong PD.
Read guide →Do You Need Your PD for Sunglasses?
Does pupillary distance matter for sunglasses? It depends on whether they're prescription. Here's when you need your PD for sunglasses — and when you really don't.
Read guide →How to Read Your Eyeglass Prescription (OD, OS, SPH, CYL, PD)
Your eyeglass prescription looks like a code, but it's simple once you know the terms. Here's what OD, OS, SPH, CYL, Axis, ADD, and PD mean — and where to find your PD.
Read guide →Glasses and Eye Terms Glossary: PD, OD, OS, SPH, and More
A plain-English glossary of the eyewear and prescription terms you'll meet when ordering glasses online — PD, OD, OS, SPH, CYL, axis, ADD, and others.
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