The amount of pee that a size 6 diaper can hold depends on the brand and absorbency of the diaper.
A size 6 diaper can hold up to 26 ounces of pee or 769 ml of pee.
The size 6 diaper should hold up to 3 wetting sessions from a toddler or child wearing the size 6 diaper.
Size 6 diapers are made for fitting children between the ages of 3 to 8 years old.
The weight range for size 6 diapers is 35 lbs to 44 lbs and over.
Size 7 diapers can hold up to 30 to 35 ounces of pee or 3 to 4 wetting sessions from a child.
However not all diapers have the same absorbency as some brands of diapers are more absorbent than others.
For example a Luvs size 6 diaper would be less absorbent than a Pampers baby dry or pampers cruisers size 6 diaper would be.
And even then a Gentle Steps size 6 or Gentle Steps size 7 diaper is much more absorbent than a Luvs size 6 or Pampers size 6 diaper.
So if your child is peeing out of a certain diaper you may need to up the size or change brands.
The Gentle Steps size 6 and size 7 diapers are much more absorbent and cheaper than the name brand diapers are.
They swell up nice and can hold a lot of pee and can fit most older kids as well.
A child wearing size 6 or size 7 diapers tends to pee less often so they will usually only need a diaper change every 3 to 4 hour as needed.
While a child or baby under 3 years old or so would need more diaper changes as they pee and poop more often.