When to Switch from Newborn to Size 1 Diapers

If you’re wondering when to switch from newborn to size 1 diapers, there are a few things to keep in mind. Here are some tips to help you make the best decision for your baby.

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Size 1 diapers generally fit babies weighing 8-14 lbs (4-6 kg). The specific range varies between brands, so it’s important to always check the weight limit on the package. Some Size 1 diapers can accommodate babies up to 18 lbs (8 kg). If your newborn is consistently on the higher end of the weight range for Size 1 diapers, you might want to consider Size 2 diapers.

When to make the switch

You may be wondering when to switch your newborn from size 0 to size 1 diapers. It’s actually not as complicated as you might think. In general, you can switch to size 1 diapers when your baby reaches 10 pounds or starts to show signs of becoming cramped in their current diaper size. Here are a few things to keep in mind when making the switch.


Weight is the biggest factor to consider when deciding when to make the switch from newborn to size 1 diapers. Most babies will need to move up to size 1 diapers by 4 to 5 months old, though some may still fit into newborn sizes at 6 months old.

However, every baby is different, so it’s important to pay attention to the diaper fit rather than weight or age when making the decision. If your baby’s diaper is starting to feel snug, especially around the legs or waist, it’s time for a bigger size. If you’re unsure whether it’s time for a larger diaper, ask your pediatrician for guidance.


When your baby reaches 18 to 24 inches in length and weighs about 8 to 12 pounds, you’ll want to switch from newborn-size diapers to size 1. Though it’s not an exact science, you can also tell it’s time to move up a diaper size if your newborn’s diaper is leaving red marks on their thighs or if the waistband feels too snug. You can also use diaper size as a general guide: A baby in size 1 diapers is ready or almost ready for solid foods, while a baby in size 2 or 3 diapers is probably eating solids.

Signs that your baby is ready

There are a few key signs that your baby is ready to move up to size 1 diapers:
-Your baby has outgrown the newborn size diapers and is leaks are becoming more frequent.
-Your baby has reached the upper weight limit for newborn diapers (usually around 10 pounds).
-Your baby is starting to sleep for longer stretches at night, and you want to avoid leaks.
-You notice that your baby’s diaper is often saggy, even when it’s not full. This can be a sign that the diaper isn’t fitting as well as it should.

How to make the switch

Congratulations on making it through the newborn stage! Your baby is growing and that means it might be time to switch to size 1 diapers. Here are a few things to keep in mind when making the switch.

Transition slowly

Size 1 diapers generally fit babies 8-14 pounds. If your baby is on the upper end of this range, you might be able to extend his time in size 0 for a bit longer by folding down the diaper’s waistband.

Proceed slowly once you start using size 1 diapers. Use them during the day for a couple of days, then at night for a couple of days, and so on until you’re confident that they provide adequate absorbency and leak protection for your baby around the clock.

Introduce new diapers gradually

Start with one new diaper a day. For example, put the new diaper on during daytime naps or at night, gradually adding more as your baby gets used to it. Once you’ve made the full switch, look for signs that your baby has outgrown size 1 diapers, such as frequent leaks or coming undone at the sides.


The bottom line is that there is no hard and fast rule for when to switch your baby from newborn to size 1 diapers. It really depends on your individual baby’s needs. However, most babies will be ready to move up to size 1 diapers sometime between 4 and 10 weeks old. If you’re unsure, it’s always best to ask your pediatrician for guidance.

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