Baby Clothing Sizes Made Simple

When you’re expecting a child, or just had one, you have a ton of things to worry about. From getting the right diapers to researching all the developmental milestones, you’ve got enough on your plate. You need someone to make baby clothing sizes simple.

It’s why we’re here to help by translating all the size markings on baby clothes. Next time you go to pick out a cute new outfit, you won’t have to worry about whether the tag says 12 months, 2T, or 56, you’ll know exactly what it means.

Different Sizing Options

The way the manufacturer labels the size of baby clothes often depends on the country where the clothes are sold.

For instance, the cute onesie you’re looking at might be labeled 3-6m in the United States, but in Germany, it’s labeled anywhere between 62-68. And in the UK, it would just be labeled 6m.

The good news is that it’s not as complicated as it sounds. Every system has logical reasoning behind it, and once you know that reason, finding out what you need becomes a lot easier.

The US System

In the United States, baby clothes are typically labeled by a month range until the child hits two years old. The entire sizing chart works off of a “typical” child. Meaning, that if your child is bigger or smaller than the typical child, the size clothing they are wearing might not match their actual age.

For baby clothes in the United States, clothing sizes are in three-month increments until the 12-month mark. After the 12-month mark, they are in 6-month increments. After 24-months the clothing is broken down by year.

So, in the United States, clothing sizes look like this 0-3m, 3-6m, 6-9m, 9-12m, 12-18m, 18-24m, 2T, 3T, 4T, and so on. After 4T, the sizing system works the same, although the T, which stands for Toddler, is typically dropped.

This system makes sense if your child grows at a typical rate, but if your child is ahead or behind the growth of an average child, the numbers soon become meaningless.

The UK System

The UK system is a bit like the system used in the United States, although they don’t use ranges for size clothing that typically fits children between 3 and 18 months. Instead, they use only the number highlighted on the high end of the child’s age range. So, if a piece of clothing is labeled 3m, it’s designed to fit a typical 3-6-month-old.

Interestingly enough, when the United States stops using age ranges, the UK starts. In the UK toddler, clothes are indicated in an age range like 2-3 for a typical 2-year-old. One other crucial difference is that the UK does not have a separate clothing size for 12-18 months like the United States.

Instead, the 12m marking on UK clothing is for children from 9 months old up to 18 months old. This means there is a significant difference in sizing for clothes marked this way. Broken down, in the UK sizing on baby and children clothes look like this: 0-3m, 6m, 9m, 12m, 18-24m, 2-3, 3-4, 4-5, and so on. 

Like the US system, the UK system is excellent for children growing at a typical rate, but if your child is bigger or smaller than an average child that age, those numbers don’t mean much.

Making Those Months Mean Something

If your child is smaller or larger than a typical child in those month ranges, how do you know what size clothes to get? And what if you don’t know if your child is a “typical height”?

Just use this chart to figure out precisely what size clothes your child needs:

Child’s height (inches)Clothing Size USClothing Size UK
22-240-3m0-3m
24-273-6m6m
27-296-9m9m
29-319-12m12m
31-3412-18m12m
34-3618-24m18-24m
36-382T2-3
38-413T3-4

The European System

Most of the world uses the metric system. That is unless you live in the United States or the United Kingdom. Then for some reason, you’re still in the imperial system.

The European clothing size makes perfect sense if you use the metric system. That big sizing chart converting your child’s height to clothing sizes? Not needed with the European system. That’s because whatever your child’s height is, in centimeters, is the size clothing they should be wearing.

Is your child is 80 cm tall? Great, a size 80 will fit perfectly. That logic follows through from children’s clothes all the way to adults. If you know how tall you are, then you know what size clothes you need.

What If You Don’t Know the Metric System?

What if you’re stuck in the imperial system, and you don’t know your child’s height in centimeters? You could multiply your child’s height (in inches) by 2.54 to get their height in centimeters, but that might seem like too much work, especially if you don’t know their current height.

Below is a chart breaking down a child’s typical age compared to their European clothing size.

Child’s AgeChild’s Clothing Size (European)
0-3 months56-62
3-6 months62-68
6-9 months63-74
9-12 months74-80
12-18 months80-86
18-24 months86-92
2 years old92-98
3 years old98-104

Baby Shoe Sizes

Now that you’ve got baby clothes down, you’re on to the next challenge: baby shoes. The good news is that it’s even simpler than baby clothes. For US sizing, all you need to do is take your child’s age (in months) and divide by three. That is typically the size shoe they need (whole number only!).

For UK sizing, take that number and subtract one (easy, right?). For some reason, the European sizing chart starts at 16. But just like the American system, add one for every three months of age. It’s super simple!

For a video with all the charts, check out the one below:

If you’re still not quite sure, here’s a helpful guide from a popular baby shoe brand.

Baby Clothing Sizes Made Simple

Knowing why something is the way it is makes it much easier to understand. Baby clothing sizes are no different. So, cross it off of your list of things to be stressed out about, and walk into the clothing store like an expert!

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