Skip to content
  1. You asked, we delivered—shop today @Target.com!
  2. Free standard shipping on all US orders $35+
What Size Diapers Do I Need?

What Size Diapers Do I Need?

One of the most common questions new parents ask is: what size diapers should I buy? If you’ve ever stood in the diaper aisle, staring at all the different numbers and weight ranges, you’re definitely not alone. Babies grow quickly, and finding the right fit is all about comfort, leak protection, and making your little one feel cozy.

Diaper Sizes by Weight

Diaper brands usually size by your baby’s weight rather than age. Here’s a general guide to help:

  • Newborn (up to 10 lbs) – Best for the earliest days when your baby is fresh from the hospital. Many babies grow out of these pretty quickly.
  • Size 1 (8–14 lbs) – Often the first go-to after newborns, fitting babies for their first couple of months.
  • Size 2 (12–18 lbs) – Usually around 3–6 months old, depending on growth.
  • Size 3 (16–28 lbs) – A very popular size, often used the longest during the first year.
  • Size 4 (22–37 lbs) – The most commonly used size overall, since many toddlers spend a lot of time here (roughly 18 months to 3 years).
  • Size 5 (27+ lbs) – For bigger toddlers who still need diapers, especially overnight.
  • Size 6 (35+ lbs) – Designed for preschoolers or older toddlers not yet potty trained.

Keep in mind that every baby is unique—your little one may grow faster, slower, or just have a different body shape that makes one size work better than another.

Nest diapers run a bit snug! Be sure to check out our sizing chart when fitting your little one.

Signs It’s Time to Size Up

How do you know if your baby is ready for the next size? Look for these clues:

  • The diaper looks snug and leaves red marks around the waist or thighs.
  • Frequent leaks or blowouts (a sign the diaper can’t contain everything).
  • Struggling to secure the tabs comfortably.
  • Your baby’s weight is at the top end of the size range.

Pro Tips for Parents

  • Don’t stockpile too much of one size. Babies can outgrow diapers overnight (literally!).
  • Mix in smaller packs. That way you’re not left with extras in the wrong size.
  • Every brand fits a little differently. If one feels too tight, trying another brand in the same size may help.

When it comes to diapers, weight is your best guide—but your baby’s comfort will tell you everything you need to know. Trust your instincts, and remember: if the diaper fits well, there will be fewer leaks, less mess, and a much happier baby (and parent!).