A diaper being too small or too big or too tight can cause the baby diaper to leak out the back.
If the diaper is leaking poop out the back then it can be a sign of the diaper being too tight or too loose and the baby is having a diaper blowout due to the poop not having enough room and then it explodes out the back.
When your baby's pee is leaking out the back of the diaper it's usually a sign that the diaper is too small or the diaper is too tight.
If the diaper is too small then you should increase the diaper size or try attaching the tabs closer to the baby's hips instead of toward the belly button.
The best way to know when to size up diapers is to stick two fingers under the waistband of the diaper that is fastened.
If you cannot get the two fingers to fit comfortably under the waistband of the diaper then you need to size up the diapers and go to the next size.
Or if you notice red marks on your baby's belly or thighs then the diaper is too small or if the diaper does not fully cover your baby's thighs or bottom then it's time for a bigger size up in diapers.
When a diaper leaks it means the the diaper is either too big or too small or not absorbent enough.
Another reason for diapers to leak is because the leg gathers are not out which you can fix by running your fingers through the leg gathers.
You want the diaper to be big enough but not too big and you don't want the diaper to be too small or it can also leak.
A diaper should be tight enough to fit like a sock would on your feet and ankles but not tight enough that it leaves marks.
When you put a diaper on your baby or toddler you should be able to get your finger under the waistband without issues and you should be able to run your fingers around the leg gathers.
A diaper that is too tight can leak and a diaper that is not snug enough can also leak.
A diaper is too small when the tabs barely reach the sides of the diaper or when there is red marks around the baby's legs or waist or if the diaper is leaking or fits like a bikini.
Diapers should cover the bottom and thighs fully and seal around the legs and fit around the waist with the tabs fitting on the Velcro strip around the middle or near the middle of the diaper.
The diapers that hold the most pee for babies is Dollar General Gentle Steps diapers, Huggies Diapers, Pampers Baby Dry diapers, Amazon Mamma Bear diapers, Kirkland Diapers and Rascal and Friends diapers.
The best diapers that don't leak in my experience are Dollar General Gentle Steps diapers which I started using with my kids a few years ago.
I was using the more expensive Huggies Snug and Dry diapers and Pampers and found that "while they are very absorbent and are good diapers" that Dollar General Gentle Steps diapers are more absorbent and don't leak like Huggies and pampers did with my kids.
It is best for diapers to be too big than too small as diapers that are too small can cause red marks and irritate the baby's skin and be uncomfortable and also leak and not hold enough pee and poop.
When diapers are bigger they hold more and don't leak or irritate the baby's skin but you don't want the diaper to be too big so that it has gaps in the legs or falls down the baby's waist as it can leak.
A proper fitting diaper is essential for your baby's or toddlers comfort and for keeping their clothes dry and preventing leaks.
The size of diapers that toddlers stay in the longest is size 3 and size 4 diapers.
The diaper that is best for leaks is Gentle Steps diapers from Dollar General which I found are even better than Pampers baby dry diapers and Huggies.
Huggies is also a good absorbent diaper that does not leak for most babies and toddlers but after trying Dollar General Gentle Steps diapers on my kids I find they are much better than Huggies and Pampers Diapers.
They are also cheaper as well.
The size of diaper that babies stay in longer is size 3 diapers up until age 1 and then after that they tend to stay in size 4 until age 2 to 3 until potty trained.
However babies and toddlers are different weights and are built different so while one baby could fit in a size 4 at age 2 or 3 another baby or toddler of the same age may need a size 5 or size 6 diaper.
The majority of babies and toddlers wear size 4 diapers up until they potty train.
Size 4 diapers are for babies and toddlers from 18 months to 3 years of age or 22 lbs to 37 lbs.
Size 5 diapers fit children 4 to 5 years old and size 6 fits children 4 to 7 years old for some kids.
Size 7 diapers fits kids between 5 years old to 8 to 10 years old and sometimes older.
After size 7 diapers is a size 8 diaper which can fit kids from 8 years old to 12 to 13 years old and sometimes older depending on how much they weigh and their build.
As babies get older they pee less and need less diapers than younger babies.
By age 2 to 3 years old most kids only need a diaper change every 3 to 4 hours depending on how much and how often they pee.
While the diaper size may appear to fit your baby, the amount of pee may have increased with their growth, so the diaper may not be able to absorb the larger amount of urine.
For disposable diapers, the bigger the size, the better the absorbency.
If you can't comfortably fit two fingers under the waistband of the fastened diaper, it's time for a bigger size.
You may need to go up a size if you notice red marks on your baby's tummy or thighs when you remove the diaper.
If the diaper isn't fully covering your baby's bottom, choose a bigger size.