How Long Are Babies In Size 1 Diapers?

The world of diapers can sometimes be overwhelming for new parents. Along with so many different brands, diapers come in several different sizes that can also be confusing and cause new questions to arise – for example, how long is a baby in size one diapers? Read on to learn how to tell when baby is ready for the next size up.


When I was preparing my daughter’s nursery for her arrival, one of the things on my mind was how many different sizes of diapers I should get and how long would she wear each size.  After doing some research, I discovered that a lot of new parents decide to forgo the newborn size diapers altogether, or only buy about a month’s worth, and move to size one right away.

So this comes back to the question, how long are babies in size one diapers?

It is important to know when to move up a size. Ultimately, the weight and length of your baby will determine how long time spent in the size ones will last. However, on average, a baby will stay in size one diapers until he or she reaches 14 pounds, which should happen by three or three-and-a-half months of age.

There are also other ways to tell if a baby should switch sizes. Dr. Sears recommends parents watch for these specific indications baby is ready to ditch the size ones (or twos and threes) and move on up in the diaper world.

To make things easier as you go, you can also check out this nifty diaper size and weight chart, provided by Pampers.

5 Signs Your Baby Is Ready For A Bigger Diaper Size

1. Tush is no longer completely covered.

It is important that a baby has adequate coverage for his bottom. If a diaper does not cover his rear sufficiently, blowouts and leaks may begin to happen on a more frequent basis and this is a definite sign that the diaper has to be upgraded.

2.  Diaper tabs are far away from little one’s tummy.

If the diaper tabs are moving further away from your baby’s tummy and are edging closer to her hips, or the wing connecting the diaper tab has become stretched out, you should probably consider switching to the next diaper size up.

3. Waistband has become too snug.

An easy way to tell if your baby’s diapers are too tiny is to check how tight the diaper is around the waist. Simply pull up slightly on the waistband with your finger and if there is a tight constriction on your finger, it is a telltale sign the diaper is probably uncomfortable for your tot. Time to move up a size!

4. Current diapers leave marks on your baby.

Another way to tell if a diaper is too tight is if your baby has chaffing and red marks in the waist, hips and groin. This is no fun for baby and it’s a sign that the time has come to make things more comfortable.

5.  Check out the diaper package or box.

Most boxes and packages of diapers will conveniently list size guidelines on the back or the side of the box, providing information about the recommended weight a baby wearing the specific diaper size should be. You should consider moving up if your baby’s height is on the lower end of the scale for the next diaper size.

Looking for the best diapers on the market?

Babylist recently polled families on the baby products they love the most, combining their own research and insight to compile a list of the best disposable diapers on the market.


Rhonda Mix

Rhonda is mom to a bright and sweet little girl. She enjoys writing for work, writing for fun and reading when time allows. Also passionate about travel, she has a fondness for Taiwan - where she once lived in a previous chapter of her life. She looks forward to all the adventures ahead and exploring new places with two of her biggest loves - her daughter and husband.

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