The Complete Guide to Baby and Toddler Sizing

One of the most unexpectedly confusing parts of parenting? Baby and toddler sizing. As if sleep deprivation was not enough, now you have to decipher sizing charts that seem more like a cryptic puzzle than an actual guide. And just when you think you have figured it out, your little one goes through a growth spurt, and that Playfully Strong Convertible Romper you just bought is already feeling snug. Sound familiar? You are not alone.

TLDR: Use height and weight first, then use age second. If you are between sizes, size up. If you use cloth diapers, size up for extra room.

Buying baby and toddler clothes should be simple, but inconsistent sizing across brands makes it a frustrating guessing game. That is why we are here to decode the madness and help you future proof your shopping. Spend less time returning ill fitting clothes and more time soaking up the snuggles.

Unlike adult sizes, baby clothes are typically labeled by age ranges (for example, 3 to 6 months, 6 to 9 months). But here is the catch. Babies do not grow on a schedule. Your little one might fit into a 3 to 6 month size at 2 months or still be rocking it at 8 months. That is why we always recommend looking at height and weight rather than just age when picking out sizes.

If you want the fastest reference point, bookmark our pajama size chart and use it any time you shop.

Here is a general breakdown:

• Newborn (NB): Up to 8 to 12 lbs, 18 to 22 inches
• 0 to 3 months: 12 to 15 lbs, 21 to 25 inches
• 3 to 6 months: 15 to 18 lbs, 24 to 27 inches
• 6 to 12 months: 18 to 22 lbs, 26 to 30 inches
• 12 to 18 months: 22 to 26 lbs, 29 to 32 inches
• 18 to 24 months: 26 to 30 lbs, 31 to 34 inches
• 2T: 30 to 32 lbs, 33 to 36 inches

But here is where things get tricky. Not all brands size the same. European brands often label sizes in centimeters (for example, 62 cm for around 3 months, 74 cm for around 6 to 9 months), which can feel more precise but still varies by brand. When in doubt, use height and weight first, then double check the brand chart. For Bam & Stitch fit details, use our pajama size chart.

If you are shopping Bam & Stitch, here is the quick reference. Use height and weight first, then use age second. If your child lands between sizes, sizing up usually gives the most comfortable fit and the longest wear.

Our bamboo zipper pajamas are designed with flexibility in mind, so your little one can stay comfy through growth spurts. If you are deciding between sizes, sizing up is the safer pick, especially if you use cloth diapers.

• Newborn: 18 to 22 inches, 8 to 12 lbs
• 0 to 3 months: 21 to 25 inches, 12 to 15 lbs
• 3 to 6 months: 24 to 27 inches, 15 to 18 lbs
• 6 to 12 months: 26 to 30 inches, 18 to 22 lbs
• 12 to 18 months: 29 to 32 inches, 22 to 26 lbs
• 18 to 24 months: 31 to 34 inches, 26 to 30 lbs
• 2T: 33 to 36 inches, 30 to 32 lbs

Want an easy starting point? Shop the Playfully Strong print, the Orchid Gardens print, or grab a favorite like the Playfully Strong Convertible Romper.

Because kids grow at lightning speed, here are some tips to make shopping easier and avoid wasting money on clothes they will barely wear:

• When in doubt, size up: If you are torn between two sizes, go bigger. A little extra room usually means longer wear.
• Choose adjustable features: Our bamboo zipper pajamas include details like fold over cuffs so you can get more wear time before sizing up.
• Stick to flexible essentials: Choose soft, breathable pieces you can use all year long, then rotate prints and styles as your child grows.
• Choose high quality bamboo viscose: With the right care, bamboo can hold up beautifully through repeat washes and hand me downs. Follow our Care Instructions to help keep fit consistent.
• Keep a stash of essentials: Stock up on basics in the next size up so you are not scrambling when your child outgrows everything overnight.