How To Measure Your PD (Pupillary Distance) – Easy Step-by-Step Guide

PD (Pupillary Distance) is the distance between the centers of your pupils. It’s a required measurement to make your prescription glasses accurate and comfortable to wear. Measuring your PD at home is quick, simple, and can be done in 1–2 minutes. This guide will show you how.

How to Measure PD Pupillary Distance

Illustration: PD Measurement Example

What Is PD?

PD is measured in millimeters (mm). Most adults have a PD between 54–74 mm. For children, it ranges from 43–54 mm. Accurate PD ensures your lenses focus light correctly for clear vision.

Tools You Need to Measure PD at Home

A ruler with millimeter (mm) markings

A mirror OR a helper (friend/family member)

Good lighting

Method 1: Measure PD by Yourself (Using a Mirror)

Stand 30–40 cm away from a mirror in a well-lit area.

Hold the ruler horizontally against your forehead, right above your eyes.

Look straight ahead and focus on your own eyes in the mirror.

Align the 0 mm mark on the ruler with the center of your right pupil.

Read the number that lines up with the center of your left pupil – this is your PD.

Repeat 2–3 times for the most accurate result.

Measure PD with Mirror

Method 2: Measure PD with a Helper (More Accurate)

Look straight at your helper’s eyes (not the ruler).

Ask your helper to hold the ruler above your eyes.

Align 0 mm with the center of one pupil.

Read the number at the center of the other pupil.

Take 2–3 measurements and use the average.

Measure PD with Helper

What Is Dual PD (Distance PD & Near PD)?

If you need progressive lenses or bifocals, you may need two measurements:

Distance PD: For daily, far vision

Near PD: For reading or close work (usually 3–4 mm less than distance PD)

Important Tips for Correct PD Measurement

Always use millimeters (mm), not inches.

Keep your eyes looking forward – do not tilt your head.

Measure 2–3 times to avoid mistakes.

If you get 62.5, round to 62 or 63 mm – both are acceptable.

You can also get PD measured during an eye exam.

LensToo Reminder

Accurate PD ensures your custom lenses provide clear, comfortable vision without dizziness or eye strain. When ordering glasses online, simply enter your PD with your prescription, and we will craft your perfect pair.

If you need help, our support team is always ready to assist you!