Back to blog

How Big is Your Child’s Bladder?

  • 2 minute read

What's a Normal Bladder?

We have previously talked about bedwetting being a normal part of growing up. As parents we know that for the most part normal is as normal does but it got me thinking about what a normal bladder does and doesn’t do. So we set about discovering and here’s what we found out.


Interestingly, some of the easiest to understand information about a normal bladder works came from the Multiple Sclerosis Trust. This is not necessarily a site you would have visited but it’s a great explanation.

Basically, a normal adult bladder holds 300-500mls of fluid (that’s about half a pint to a pint) and we typically empty our bladders between 6 and 8 times a day.

Children Have Smaller Bladders

Children are of course smaller and with all their activity they can sweat out quite a lot of fluid in a day – so for them, the normal range for bladder emptying is between 4 and 8 times a day.


And one of the most interesting discoveries we found is that there is actually a formula for calculating your child’s approximate bladder capacity! Here it is…


Age of child x 30 + 30 = average bladder capacity in mls. For example, for a 6 year old child you calculate it as follows: 6 x 30 + 30 = 210 mls


Calculation sourced from ERIC  http://www.eric.org.uk/


Of course, this figure is an average so if your child is substantially smaller or bigger than other children their age, their bladder capacity’s likely to differ too. Either way, it’s reassuring to know that our  Brolly Sheets hold up to 2 litres so they’ll never let you down.


We know as a parent of a child who wets the bed it can be really hard to get some straight forward facts. We hope this helps. If you do notice unusual bladder capacity in your child, it’s easy to have a chat with your family doctor. But for most of you, now you know what “normal” is, you can at least put that nagging worry to rest.


Sleep easy, Diane.