Here’s a question I got asked at my own baby shower, standing next to a pile of adorable tiny clothes. “So how many onesies do you actually need?” And honestly? I had no clue. I just knew everything in front of me was impossibly small and impossibly cute.

Turns out, most parents way overbuy in the newborn size and then scramble later when baby hits three months and suddenly nothing fits. So let’s fix that. Here’s an actual breakdown of how many pieces you need in each size, based on what real parents use, not what looks good stacked up for a registry photo.

Newborn Size: Buy Less Than You Think

This one surprises people every time. Newborn size clothes fit for a shockingly short window. Some babies skip this size almost entirely if they’re born on the bigger side.

A good number here is about five to seven onesies, max. You really don’t need more than that. Add two or three sleep gowns and maybe one or two going-home outfits in case your baby ends up small.

Why so few? Because babies grow out of newborn size sometimes within two to three weeks. I bought a dozen newborn onesies with my first baby, and half of them never got worn. They just sat in a drawer while my daughter jumped straight into 0-3 month clothes by week three.

If people ask what to bring to your shower, tell them to skip heavy newborn purchases. Ask for a range of sizes instead, or gift cards you can use once baby’s actual size becomes clear.

0-3 Month Size: Your Real Workhorse

This is where your baby will likely live for the longest stretch, so stock up a bit more here. Aim for around eight to ten onesies, three or four sleep gowns, and a handful of pants or leggings if you like layering.

Babies spit up, blow out diapers, and generally destroy clothes faster than you’d expect. Having enough 0-3 month pieces means you’re not doing laundry every single day just to keep baby dressed.

Sleep gowns deserve extra love in this size. They make nighttime diaper changes so much faster, since you’re not wrestling tiny arms through sleeves at 2am while baby’s already upset. Trust me, future you will be grateful.

Add a couple of light jackets or sweaters too, depending on the season baby’s born into. You don’t need much here, just enough to handle whatever weather shows up during these months.

3-6 Month Size: Room to Grow

By this point, you’ve got a better sense of your baby’s growth pattern, so this is a safer size to stock up on a bit more confidently. Aim for eight onesies, a couple sleep gowns, and some pants or rompers depending on your baby’s mobility.

This is also when a lot of babies start rolling over and moving more, so clothes with a little stretch matter more than they did before. Skip anything too stiff or restrictive.

Socks become more important here too, since babies start kicking their shoes and socks off constantly (fair warning, you’ll lose approximately one sock per week to the laundry void). Buy a few extra pairs just to keep up.

6-9 Month Size: Getting Practical

Feeding season hits hard around here, so bibs and stain-resistant fabrics become your best friend. You’ll want around six to eight onesies, some rompers, and a few pairs of soft pants for crawling babies.

This is where knees matter. Babies crawling on rough floors need pants with a little extra durability, since bare knees on hardwood get rough fast. A few pairs of leggings or joggers with reinforced knees save you some wear and tear on baby’s skin (and your patience).

You’ll also want a couple of warmer layers if baby’s hitting this stage during colder months. A light sweater or two, plus a warm hat for outings, rounds this size out nicely.

9-12 Month Size: Prepping for Walking

Clothes here need to move with baby, since a lot of little ones are pulling up, cruising, and maybe even taking those first wobbly steps. Look for pants and rompers with a bit of stretch and flexibility.

Aim for six to eight onesies still, plus a good mix of pants and shirts you can layer depending on the weather. Soft-soled shoes belong here too, though bare feet indoors actually help with balance and are totally fine.

Ask yourself this: is my baby close to walking yet? If yes, prioritize clothes that don’t restrict leg movement. Baggy overalls and stiff jeans might look cute in photos, but they can genuinely slow down a baby learning to move.

A Few General Rules That Apply to Every Size

No matter what size you’re shopping for, a few things stay consistent. Snaps beat buttons every time, especially down the front or with a crotch snap for easy diaper changes. Save the cute button-up outfits for special occasions, not everyday wear.

Soft, breathable fabric matters more than pattern or color. Cotton works well in most climates and won’t irritate baby’s sensitive skin the way some synthetic blends can.

Buy fewer pieces than you think you need, and buy them gradually as baby grows instead of all at once. It’s tempting to stock up early, especially during a cute sale, but sizing surprises happen constantly. Some babies skip sizes entirely. Others linger in one size for months longer than expected.

The Biggest Mistake Parents Make With Baby Clothes

Want to know the number one thing I’d tell any pregnant friend building a clothing registry? Don’t buy everything upfront. It feels productive, sure, but half of what you buy for a future size might not even fit right when the time comes.

Ask for gift cards for clothing instead of specific items when possible. That way, once you actually see how your baby’s growing, you can buy exactly what fits instead of guessing months in advance.

My friend Rachel bought a whole wardrobe of 6-month clothes while pregnant, all in adorable matching sets. Her son ended up big for his age and skipped that size almost entirely, jumping from 3 months straight to 9 months. She donated almost everything unworn.

Laundry Realities Nobody Warns You About

Here’s something that catches new parents off guard. You’ll be doing baby laundry way more often than you’d expect, sometimes daily during blowout-heavy weeks. Having enough clothes in rotation matters, but having too many just means more stuff to store and eventually give away.

A good general rule is having about a week’s worth of outfits in whatever current size baby’s wearing. That way you’re not desperately doing laundry at midnight, but you’re also not drowning in unworn clothes taking up drawer space.

Seasonal Considerations Worth Thinking About

If your baby’s born in summer, you’ll need less bulky stuff and more light, breathable onesies. Winter babies need warmer layers, hats, and maybe a few footed sleepers with extra warmth built in.

Think about what season each size will actually fall during, not just what season baby’s born in. A baby born in October might hit the 6-month mark in April, which means warm weather clothes matter more than heavy winter gear at that stage.

This part trips people up constantly. Planning ahead by season, not just by current weather, saves you from buying a stack of sweaters your baby will barely wear before it’s suddenly summer.

Bringing It All Together

Here’s the simple version. Buy light in newborn size, stock up a bit more in 0-3 months since that’s where baby lives longest early on, and then buy gradually as you go, size by size, watching how your particular baby grows.

Skip buying everything at once, no matter how tempting those matching outfit sets look in the store. Babies are unpredictable, and clothes you love now might sit unworn if baby skips a size or grows in an unexpected direction.

At the end of the day, your baby doesn’t care if they’re wearing the same three onesies on rotation all week. They just want to be warm, comfortable, and close to you. Everything else? That’s just extra, and it’s completely okay to keep it simple.