Why Age Isn't Enough to Choose Kids' Clothing Size

Michael Dsouza @ Sep 23, 2026

Introduction

“She's 5 years old, so should I buy size 5?”

It sounds simple, but children's clothing sizes aren't always that straightforward.

Two children of the same age can have completely different heights, body proportions and growth patterns. That's why choosing children's clothing based only on age can sometimes result in clothes that are too tight, too loose or too short.

Why age-based sizing can be confusing

Age is only an approximate indicator of size.

For example, two 6-year-old children could have different:

Heights
Chest measurements
Shoulder widths
Body proportions
Growth rates

This is especially important when buying clothes online because you cannot physically try the garment before purchasing.

Height can be more useful

When choosing children's clothing online, height can provide an additional reference point.

Parents should ideally compare their child's current height with the brand's size chart.

Don't ignore the size chart

A good kids' size chart may include:

Age
Height
Weight
Chest
Shoulder
Waist or hip measurements

Not every measurement will be equally important for every garment.

For a top, for example, chest and shoulder measurements may matter more than hip measurements.

Measure your child correctly

Parents don't need professional measuring equipment.

A simple measuring tape can help.

For height:
Have the child stand straight against a wall without shoes.

For chest:
Measure around the fullest part of the chest without pulling the tape too tightly.

For shoulder:
Measure across the shoulders according to the brand's instructions.

What if your child is between two sizes?

This depends on the garment and the child's body shape.

If the child is close to the upper end of a size range, parents may want to consider the next size, particularly if the garment is not designed to be fitted.

But don't automatically size up for every product.