What size should I get? Predicting your newborn baby's size for a coming home outfit.

June 13, 2016 3 min read 2 Comments

One of the most common questions I get from customers here at Cuddle Sleep Dream is, "What size should I get?".

Especially for newborns, this is a tough one!

Babies can be 1-12 lbs at birth, (though most are 6-9 lbs) and can grow at all different rates.  

Then of course, you have to factor in his length.  

And if you are shopping for a baby who is not even here yet, how can you possibly guess??

Roman was 8lb 5oz, 20" and is wearing NB.

We've dressed about 10,000 babies over the past 3 years in our baby boy coming home outfits, so here's how we help moms figure out what size to get for babies that have't arrived yet! 

Generally speaking, if you are shopping for a coming home outfit, we recommend getting a size Newborn. 

Here's why:

Size newborn is for babies 5-8 lbs, and up to 21.5", but even most babies up to 9 lbs or so will fit better in size newborn for at least a few days

My first son Jason was 8lb 13oz, 21" and wore size newborn for about a week.


Well, for one thing, babies lose up to 5-10% of their birth weight in the first week (the lower end if you formula feed and the higher end if you breastfeed). That weightloss can happen very quickly too! A hospital sometimes won't discharge you right away if baby has lost more than 10%, but he'll almost definitely be smaller when you are sent home 1-3 days later than when he was born! 

Secondly, your newborn's length will also affect his clothing size. The average length of a newborn baby is 20" with a normal range of 18-22". They also tend to be all scrunched up for a while, so they don't exactly pull and stretch at clothes. 

My second son Leo was 8lb 6oz, 20" long and he wore size newborn for a full month.

There are 3 exceptions to our size Newborn recommendation for take home outfits.

1. If this is not your first baby, and your earlier babies were 9+ lb and you know they didn't fit in size Newborn... then you are probably not even reading this blog post because you know 3m is what you'll need! 

big newborn baby

Donovan was 10lbs and is wearing size 3m.

2. Similarly, if your doctor is predicting your baby is going to be gigantic, you may want to at least consider size 3m instead.  That said, ultrasound predictions are often wildly off.  Personally I would trust a doctor or midwife who is manually feeling your belly with a size prediction, but not an ultrasound.  And keep the length thing in mind.  Even heavy babies can be short! 

tiny newborn baby size

River was 5lbs 11oz at 5 weeks early and is wearing size NB.

3. If you are planning at Newborn photoshoot at 3-4 weeks and need to re-use the outfit. Most newborn shoots happen within 1-2 weeks after birth and a size Newborn should still be fine.  But if you are planning to have it a little later, you may find he'll be more comfortable in a 3m.  

Some quick general growth tips:

  • Average baby BOY size at birth: 7.5 lbs, with 95% of babies falling between 5.5-10 lbs
  • Average weight loss: 5-10% in the first week
  • Average weight gain the first month: Most babies regain their birth weight by 2 weeks old. Then they gain about 1 oz/day the first month, meaning they will gain 1.5-2 lbs in their first month.

I hope that helps!

But remember, our non-personalized coming home outfits outfits are always able to be exchanged or returned for any reason. (And some moms even buy both the NB and 3m!)

newborn baby boy size

Brody was 8lb 2oz, 20in, and is wearing size Newborn.

    Ryann Kahn
    Ryann Kahn

    2 Responses


    October 04, 2016

    Definitely helpful for any new moms out there! Looking back at it now I wish I went with both newborn and 3 Month size for his coming home outfit.


    October 03, 2016

    Super Helpful ! Was Unsure Of Correct Size To Have For Brand New Baby.

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