Children’s Clothing: Our Size Guide

If you have ever ordered what looked like the perfect outfit only to have it swim on your child, or barely last two washes before it is suddenly too short, you already know the struggle. Kids grow in bursts, brands size things differently, and an age label on a tag rarely tells the whole story. This children's clothing size guide breaks measurements down stage by stage, so you can shop with a little more confidence and a lot less guessing.

Why Age Alone Does Not Tell the Whole Story

Two kids born the same week can be wearing completely different sizes by the time they start school. Growth is not a straight line. It comes in spurts, slows down, then picks back up again, often without warning. That is exactly why brands (ours included) tie sizing to height and weight ranges rather than age alone.

Genetics, diet, and even the season play a role in how fast a child grows. So while age is a handy shorthand on a size tag, treating it as a strict rule is where most sizing mistakes happen.

Quick Reference: Height by Age

Height is the most reliable way to find the right size, so here is a condensed look at our official chart, pulled straight from our size guide. If your child falls near the edge of a range, sizing up is usually the safer call.

Age	Height
3 months	55 to 60 cm (21.5 to 23.5 in)
12 months	71 to 74 cm (28 to 29 in)
24 months	82 to 86 cm (32.25 to 33.875 in)
36 months	93 to 98 cm (36.5 to 38.5 in)
4 years	99 to 104 cm (39 to 41 in)
5 years	105 to 110 cm (41.375 to 43.25 in)
6 years	111 to 116 cm (43.75 to 45.625 in)
7 years	117 to 122 cm (46 to 48 in)
8 years	123 to 128 cm (48.5 to 50.375 in)
9 years	129 to 134 cm (50.75 to 52.75 in)
10 years	135 to 140 cm (53.125 to 55.125 in)
12 years	141 to 152 cm (55.5 to 59.875 in)
14 years	153 to 158 cm (60.25 to 62.25 in)
16 years	159 to 164 cm (63 to 64.5 in)

For chest, waist, and hip measurements too, our full size chart has the complete breakdown by age, all the way up to size 16.

Baby Sizes: 3 to 36 Months

This is the stage where growth moves fastest, which also makes it the trickiest to shop for. A baby can outgrow a size in a matter of weeks during the first year, then growth tends to slow down a little through the toddler months.

A few things that help:

• Avoid stocking up too heavily on any single size, especially under 12 months.
• Look for pieces with a bit of stretch or adjustable snaps, which buy extra wear time.
• Check chest and length measurements rather than relying on "3M" or "24M" labels alone, since these vary between brands.

Kids' Sizes: 4 to 8 Years

Once children hit preschool and early elementary years, growth becomes a bit steadier, but proportions start to differ more from child to child. A 6 year old might be tall and lean, or shorter and sturdier, and both can be perfectly average.

This is a good age to start taking real measurements instead of guessing from a birthday. It takes two minutes and saves a return trip to the mailbox.

Tween Sizes: 9 to 14 Years

Somewhere in this range, the early signs of a growth spurt tend to show up, and it can be sudden. A child who was comfortably in a size 10 might need a 12 within a few months. Waist and height differences also become more noticeable at this stage, which matters a lot for fitted pieces.

If your daughter is shopping for dresses specifically, our guide to dress sizing walks through the exact measurements that matter most for that category, since fit works a little differently for dresses than for everyday basics.

How to Measure Your Child at Home

A proper measurement takes less time than reading this paragraph, and it is the single best way to avoid a return. Here is what to check:

Height

Have your child stand straight against a wall, without shoes, and measure from the top of the head to the floor.

Chest

Wrap a soft measuring tape around the fullest part of the chest, keeping it level and not too tight.

Waist

Measure around the natural waistline, just above the belly button, with the tape relaxed rather than snug.

Once you have these three numbers, compare them against our complete size chart, which also lists chest, waist, and hip measurements for every size we offer, from 3 months up to 16 years.

Growth patterns can vary quite a bit from one child to another, and organizations like the Canadian Paediatric Society track this closely to help parents understand what a healthy range of growth looks like. It is a good reminder that there is no single "normal" when it comes to how kids grow in height.

Should You Size Up?

Generally, yes, with a small caveat. Buying one size ahead is a common trick for a reason: it extends how long a piece stays wearable, especially for outerwear, sweaters, and anything without a strict fitted cut. A size 5 top on a 4 year old will usually work just fine and last well into the following year.

The exception is anything with a more precise fit, like fitted pants or dresses with a defined waist, where sizing up too far can mean bunching fabric or a hem that drags. For those pieces, sticking closer to your child's actual measurements tends to work better than sizing up blindly.

Shopping Smart for Growing Kids

A few habits make the whole process easier over time:

• Re-measure every few months, especially around ages 2 to 3 and again around 10 to 12, when growth tends to speed up.
• Keep a running note of your child's current measurements somewhere handy, like your phone, so you are not guessing at checkout.
• Do not be afraid to size down for a specific item if your child runs small for their age. Comfort matters more than matching a birthday number.
• Take advantage of free returns when a size does not work out. It happens to every parent, even the ones who measure carefully.

Whether you are shopping our girl or boy collections, keeping a current measurement on hand is still the fastest way to skip the guesswork and get straight to the fun part: picking out something they will actually want to wear.

For head sizing specifically, whether it is a winter hat or a summer cap, our hat sizing guide covers that measurement too, since it works a little differently from clothing sizes.

Frequently Asked Questions

What size is a youth medium?

"Youth medium" is not a label we use here, since our sizing runs by age and height instead. As a general industry reference, youth medium usually fits kids around 8 to 10 years old, though this varies by brand. Matching your child's height to our chart above is the more reliable way to land the right size with us.

What size does a 10 year old wear?

Based on our chart, a 10 year old typically measures between 135 and 140 cm, which lines up with our size 10. That said, height varies more than age at this stage, so some 10 year olds fit closer to a size 9 or a size 12.

How do I know when to size up?

Size up when your child measures near the top of a size range, when you want extra room to grow into, or when the piece is not fitted, like a sweater or a jacket. For fitted items such as dresses or tailored pants, sticking closer to their actual measurements tends to work better.