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 center each prescription lens over the eyes. On our product pages, PD Range is based on the frame numbers: lens width + bridge width gives the frame PD, and most optical frames fit from about 8 mm below that number up to that number.
Don’t worry, it’s easy to measure at home! Most kids have a PD between 43–66 mm.
What You’re Measuring
The distance from the center of one pupil to the center of the other
3 Easy Steps
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.
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.
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.
Typical PD by Age
These are averages — every child is different, so always measure when you can!
Ages 1–4
Toddlers
43–54 mm 🧒Ages 5–8
Little Kids
48–58 mm 🎓Ages 9–12
Big Kids
52–62 mm 😎Ages 13+
Teens
55–66 mmTips 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
- After measuring, compare the number with the PD Range on each product page
Got your measurement? Let's find the perfect frames!