How to Measure Your Child's PD

It only takes a minute, and we'll walk you through every step!

What is PD?

PD stands for Pupillary Distance — it’s simply the distance (in millimeters) between the centers of your child’s two pupils.

Opticians use this measurement to make sure the lenses in your child’s glasses are centered perfectly over their eyes. Getting it right means clearer, more comfortable vision — especially for prescription lenses.

Don’t worry, it’s easy to measure at home! Most kids have a PD between 43–58 mm.

What You’re Measuring

The distance from the center of one pupil to the center of the other

PD

3 Easy Steps

1

Grab a Millimeter Ruler

Use a regular ruler with millimeter markings. A flat, straight ruler works best — avoid flexible tape measures for this one. If you don’t have one handy, you can print a free PD ruler from your optician’s website.

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2

Have Your Child Look Straight Ahead

Stand at arm’s length facing your child, at their eye level. Ask them to look at something straight ahead (a sticker on your forehead works great!). Keep both of their eyes open and focused on the same spot.

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3

Measure Between the Pupils

Place the ruler gently across the bridge of their nose. Line up the “0” with the center of one pupil, then read the number at the center of the other pupil. That number (in mm) is their PD! Measure 2–3 times and use the average for the best result.

50 mm

Typical PD by Age

These are averages — every child is different, so always measure when you can!

👶

Ages 1–3

Toddler

39–43 mm
🧒

Ages 4–6

Preschool

43–48 mm
🎓

Ages 7–9

School Age

48–52 mm
😎

Ages 10–13

Tweens & Teens

52–58 mm

Save Your Child’s PD

Enter the measurement below and we’ll remember it for when you order

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Tips for an Accurate Measurement

  • Measure 2–3 times and take the average — it’s normal to be off by 1–2 mm
  • Make sure your child is looking at something at eye level, not up or down
  • Use good lighting so you can clearly see their pupils
  • If your child’s prescription includes a PD number, use that — it’s already been measured by a professional
  • Not sure? No worries — ask Buddy and we’ll help you out!

Got your measurement? Let’s find the perfect frames!

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