What Size Baby Clothes Should You Buy? (A Simple Guide for Baby Gifts)

Buying Baby Clothes Sounds Simple… Until It Isn’t

My idea to write a size guide occurred to me when my friend texted me, and said, “I’m on your website, and I want to buy the Local Chick shirt for my niece who’s 3, but I only see 2T, 4T, and 6T. Which size should I get?

If you’ve ever stood in front of a rack of baby clothes wondering “What size should I actually buy?” — You’re not alone.

For grandparents, aunts, and friends shopping for baby shower gifts, this is one of the most common questions.

The truth is: babies grow quickly, and sizing isn’t always straightforward.
But with a little guidance, you can choose a size that’s both practical and appreciated.

 

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Understanding Baby Clothing Sizes

Baby clothing sizes are typically based on age ranges, but every baby grows differently.

Here’s a general guide:

• Newborn (NB): 5–8 lbs (fits for only a few weeks)

• 0–3 months: 8–12 lbs

• 3–6 months: 12–16 lbs

• 6–12 months: 16–22 lbs

Important: These are estimates; some babies skip sizes entirely.

 

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The Most Common Mistake Gift-Givers Make

Buying newborn size.

While it’s adorable, most parents receive a lot of newborn clothing, and babies often outgrow it within weeks. According to the World Health Organization, the average birth weight of a full-term male baby is 7 lbs 6 oz or 3.3 (Kg) and the average birth weight of a full-term female is 7 lbs 2 oz or 3.2 (Kg) 

And, I like to remind people that babies arrive very small, they do not come out like chicken breasts. That 7 lbs includes their entire body: arms, legs, head, etc.! Many people laugh when I remind them of that fact!

Additionally, babies lose around 10% of their weight during the first week after birth. It is largely due to fluid loss and usually nothing to worry about. Most babies gain back this weight within 1 week.

Here is a weight chart from the World Health Organization.

The chart below shows baby weights in the 50th percentile, which refers to the average weight. Male babies tend to weigh a little more than female babies, so the chart divides into sex. 

Babies typically double their birth weight by 4 months and triple their birth weight by their first birthday;

 

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The best size to buy as a gift when the child has not been born or was born in the last month. 

A Safe Choice

• 3–6 months (great for longevity)

Smart strategy:

Buy a size the baby will grow into, not just wear immediately.

This gives parents something to look forward to and ensures your gift doesn’t go unused.

 

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Think About the Season

A helpful tip most people overlook–

Ask yourself:

• How old will the baby be during summer?

• What size will they be during the holidays?

For example:

• A winter baby → 3–6 month outfits for spring

• A summer baby → 6–12 month outfits for fall

This makes your gift feel extra thoughtful and practical.

 

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Why Slightly Bigger Is Always Better

When in doubt, size up.

Benefits:

• Babies grow fast

• Parents can layer clothing

• Your gift gets worn longer

A slightly bigger outfit is always more useful than one that’s outgrown too soon.

 

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Fabric Matters Just as Much as Size

Beyond sizing, parents care deeply about comfort and safety.

Look for:

• Organic cotton

• Breathable, soft materials

• Non-toxic dyes

 

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Choose Pieces That Grow With the Baby

Some outfits are more flexible than others.

Look for:

• Stretchy fabrics

• Simple, comfortable fits

• Onesies that allow room to grow

These pieces last longer and get more use.

Make Your Gift One They’ll Actually Use

The best baby gifts aren’t just cute — they’re practical.

By choosing the right size, you:

• Save parents from returns

• Ensure your gift gets worn

• Become the person who “got it right”

And that always stands out.

Understanding Baby & Toddler Clothing Sizes

Extended Sizes (Very Helpful for Gift-Givers)

• 12–18 months: ~22–27 lbs

• 2T (2 Toddler): ~27–30 lbs

• 4T: ~34–39 lbs

• 6T: ~45–50+ lbs

 

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What Most Gift-Givers Don’t Realize

• Babies grow quickly in the first year, but growth slows slightly in toddler years

• Toddler sizes (2T, 4T, 6T) are based more on height and proportions, not just weight

• Many parents appreciate receiving larger sizes (12–18 months and up) because:

• They last longer

• They’re less commonly gifted

• They’re useful when the baby “outgrows everything overnight”

 

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🎯 Pro Tip for Grandparents & Gift Buyers

If you want your gift to stand out:

• 3–6 months for immediate use

• OR

• Buy 12–18 months or 2T for a future surprise parents will truly appreciate

At Simply Chickie, our sizes run large! In the toddler sizes, our 2T fits a 2-3 year old, our 4T fits a 4-5 year old, and our 6T fits 6-7 year old.

Shop Thoughtful Baby Gifts

Looking for high-quality, perfectly giftable baby clothing? Explore Simply Chickie Clothing designed for comfort, meaning, and real-life use.

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