One size nappies

Continuing with our look at cloth nappy terms, today I’m going to talk about one size nappies. There are actually lots of different things that these cloth nappies are called. We’ll take a look at some of the different names for them and see if those different names actually mean that the nappy is different in some way.

One size nappies

Cloth nappies usually come in two different types; sized nappies, which mean that you will need to buy new sizes as your baby grows and one size nappies, that come in just one size. As a general rule one size nappies tend to have some method to adjust them to fit a range of different sizes of babies, although it is possible that a one size nappy may just come in one size and fit just one size. There is, just to confuse things slightly, a third type of nappy that is sized, but then has adjustments to make it fit a range of sizes within that size range.

Birth to potty nappies

When I first started using cloth nappies, most of the one size nappies were known as birth to potty nappies. The idea being that this one nappy would fit your baby from birth, until they stopped using nappies, they went from birth to potty. Sadly, most one size nappies don’t actually fit right from birth, you usually have to wait until your little one is at least a few weeks old, and in some cases a few months old. They often don’t fit right up to toilet training either, depending on how old your little one is when they stop using nappies, and how big they are. For this reason, individual cloth nappies tend not to be called birth to potty nappies any longer.


Often you will see one size nappies called OSFA nappies, which stands for one size fits all. For a while this was the preferred name for nappies that you could adjust to fit a range of sizes. There as a bit of a problem with this particular term though, all babies are different and come in a range of sizes and shapes. There is no nappy on the market that will fit all babies or work for all babies. For this reason the term OSFA tends not to be used that often any more.


As people went of using OSFA as a term, OSFM became popular, it stands for one size fits most. Most one size nappies on the market that are designed to fit a range of sizes are sold as being OSFM today. OSFM generally will fit the same range (or in some cases a better range) of sizes as those listed as OSFA nappies, it is just an attempt to give a more accurate description of size.

One size nappies; dinky osfm

I hope that helps to explain what a one size cloth nappy is, well be looking at some more common cloth nappy terms soon.

If you want to know more about using cloth nappies on your baby, check out our free cloth nappy advice service.

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