How to Measure Your PD (Pupillary Distance) at Home

If your prescription does not include your PD, do not worry - you can measure it yourself in just a few minutes. This step-by-step guide shows you how to measure your Pupillary Distance (PD) accurately at home using simple tools. We also explain common mistakes to avoid so you can submit your prescription details with confidence.

Accurate PD = crystal clear vision.

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What Is Pupillary Distance (PD)?

Pupillary Distance (PD) is the distance in millimeters between the centers of your pupils. It ensures your lenses are aligned correctly with your eyes’ optical centers.

If PD is even slightly off, you may experience:

  • Blurry vision
  • Eye strain
  • Headaches
  • Distorted peripheral vision

Single PD vs Dual PD

Single PD
One total number (example: 62mm).

Dual PD
Two numbers (example: 31/31). This measures each eye separately from the center of your nose.

Dual PD is slightly more precise, but single PD works perfectly well for most prescriptions.

Why PD Is Important for Prescription Lenses

When we replace lenses in your frames, the optical center of each lens must align with your pupils. If PD is incorrect:

  • The lens center will not align with your pupil
  • Your prescription may not perform as designed
  • You may feel discomfort right away

That is why we always recommend confirming your PD before ordering. If your prescription does not list PD, that is completely normal - many optometrists leave it off.

You can request it from your doctor, or measure it at home using the methods below.

Method 1 - Mirror + Ruler Method (Do It Yourself)

This is the easiest method if you are measuring alone.

What You Need:

  • A millimeter ruler (mm only - not inches)
  • A mirror
  • Good lighting

Step-by-Step Instructions:

  • Step 1: Stand about 8 inches away from a mirror.
  • Step 2: Hold the ruler flat against the bridge of your nose.
  • Step 3: Close your right eye.
  • Step 4: Align the 0mm mark with the center of your left pupil.
  • Step 5: Open your right eye and close your left eye.
  • Step 6: Look at the number that lines up with the center of your right pupil.

That number (in millimeters) is your PD.

Accuracy Tip:

Measure 3 times. If you get slightly different numbers, take the average. Most adult PDs range between 54mm and 74mm.

Method 2 - Friend-Assisted Method (More Accurate)

If someone can help you, this method is slightly more precise.

Instructions:

  1. Sit or stand upright.
  2. Look straight ahead at a distant object.
  3. Your helper places the ruler across your nose.
  4. They measure from the center of one pupil to the center of the other.

Make sure:

  • You are not looking at the ruler
  • Your head stays straight
  • The ruler is level

This method reduces parallax error.

Common PD Measurement Mistakes

Avoid these common errors:

  • ❌ Measuring in inches instead of millimeters
  • ❌ Tilting the ruler
  • ❌ Measuring from the edge of the pupil instead of the center
  • ❌ Leaning forward toward the mirror
  • ❌ Looking at the ruler instead of straight ahead

Small errors can cause noticeable discomfort, so take your time and repeat the measurement for accuracy.

What If My Prescription Doesn’t Include PD?

This is extremely common. Many eye doctors do not automatically include PD because it is not required for a medical prescription - only for eyewear manufacturing.

You can:

  • Call your optometrist and request it
  • Measure it at home using this guide
  • Contact our support team for help

We are happy to help double-check your numbers before processing your lenses.

Single PD vs Dual PD - Which Should I Enter?

If your prescription shows:

62mm → Enter as single PD.

If it shows:

31 / 31 → Enter each number separately.

If your Shopify product page allows only one field, simply add the two dual numbers together.

Example: 31 + 31 = 62mm

Is Measuring PD at Home Accurate?

Yes - when done carefully.

Home measurement is typically accurate within 1mm, which is acceptable for most prescriptions.

For very strong prescriptions (±6.00 and above), professionally measured dual PD is ideal - but not mandatory.

Frequently Asked Questions

What is a normal PD range?
Most adults fall between 54mm and 74mm. Women often average slightly lower than men.

Can I order lenses without PD?
Technically yes - but it may reduce visual comfort and accuracy. We strongly recommend including it.

Is dual PD better than single PD?
Dual PD is slightly more precise, especially for high prescriptions.

What if I enter the wrong PD?
If you are unsure, contact us immediately after placing your order. We can usually adjust before lens cutting begins.

Need Help Confirming Your PD?

If you are unsure about your measurement, you can contact us before checkout.

  • Email us your prescription
  • Send a photo of your measurement
  • Ask us before completing checkout

We are here to make the process simple and stress-free.