A pair that doesn't fit ends up in the bag. UV protection only works when sunglasses stay on a child's face, and an uncomfortable child will quietly take them off. So before colour or shape, there's one question to answer: are they the right size?
Here is an age-by-age guide to kids' sunglasses sizes, the measurements that matter and three quick fit tests to try at home.
Key takeaways
- Fit for now: never size up to grow into sunglasses. Loose frames slide down and let light in around the edges.
- Bridge width matters most: it decides whether frames sit securely or slide down the nose.
- The 10-minute rule: if your child wears them for 10 minutes without complaint or deep red marks, the fit is right.
The 3 measurements that decide everything
- Lens width: the horizontal size of each lens. It decides coverage.
- Bridge width: the gap between the lenses where the frame rests on the nose. The most underestimated measurement.
- Temple length: the arm from the hinge to the ear tip. Too short and it pinches; too long and it wobbles during play.
Each product page lists the exact measurements for that model, and our sunglasses size chart shows every size side by side.
Kids aren't small adults. Children's nose bridges are flatter and their cheekbones sit differently, so OLIVIO&CO frames are designed for children's faces rather than scaled down from adult styles.
OLIVIO&CO sizes by age
Toddler & Baby (0–3 years)
Soft, light TPEE frames with rounded edges and lenses that cover the whole eye area. Check that the sunglasses stay in place when your child tilts their head, and that no light leaks in from the sides.
Shop baby sunglasses · Shop toddler sunglasses
Kids XS (3–5 years)
Flexible TR90 frames for busy preschoolers, with a forgiving fit. Check for no red marks on the bridge or behind the ears after 10 minutes.
Kids S (3–7 years)
Round, oval, Square-D and sport shapes. This is when kids start choosing their own style. Check that the frame stays put when your child runs and stops suddenly.
Shop Kids 3–7 sunglasses · Kids 3–7 sport sunglasses
Youth M (7–12 years)
Closer to adult styling, with bridge widths and curves still sized for younger faces. Check that lenses don't touch the eyelashes and that they're comfortable for a full afternoon outside.
Shop Youth 7–12 sport sunglasses · Youth Square-D – Tortoiseshell
Teen & Adult (L/XL, 12+ years)
Full-size frames for teens and grown-ups. Shop Teen & Adult sunglasses
The 3 at-home fit tests
- The 10-minute wear test: normal play for 10 minutes. Complaints or quick removal mean the fit is off.
- The red-mark check: faint marks are normal; lingering red marks on the nose or behind the ears mean the frame is too small or tight.
- The look-at-your-shoes test: ask your child to look down at their feet. The sunglasses should stay in place.
If any test fails, exchange for a different size. We offer easy exchanges and 30-day returns.
When is it time to size up?
- The frame leaves red marks where it used to fit.
- The lenses no longer cover up to the brow line.
- Your child suddenly stops wearing them, often a silent sign of discomfort.
Rule of thumb: expect to change size every 12–18 months up to about age 8, and every 2–3 years after that.
Frequently asked questions
How do I measure my child's face for sunglasses?
Start with the bridge: measure across the top of the nose where the frame will rest, in millimetres, and compare with our size chart.
Should I buy a bigger size so it lasts longer?
No. Oversized sunglasses slip, let UV in around the edges and usually end up in a bag.
What if a pair breaks?
Every OLIVIO&CO pair has a 13-month warranty. Contact our customer service team for help.
