Childrens clothing sizing?

[NillyFrickers]

I'm so confused, I have a DD and she is currently in 18-24m.
Most clothing is labelled as 1-2, 2-3- 3-4 etc
So I know obviously the age in which these are supposed to fit (on average)

So I have been looking at some outfits for a holiday, but they are sized as 2 years, 3 years, 4 years etc.

My question is... what size do they fit?
For example is the size "2 years" UP TO 2 years so 1-2 kind of thing, or is it FROM 2 years, so 2-3?

I know this sounds silly but I'm finding it quiet difficult to figure this out as it's only online shops that I've come across to size their clothes like this so I'm unable to try them on.

I know this may not belong on this forum section but this is the busiest I find.

TIA

My ds turned 2 yesterday and it's generally quite tall for his age I think so he's been wearing 2-3 for a few months.. He just got new jeans from gap and ended up going for 2 and they seem about right if not a little big so I think it goes 18-24, 2 then 3? Or gap night just have really big fitting trousers not sure 🙈

Roughly I would say 2 is 2-3 but I have found the ages on clothes don't always match the children's ages exactly. However they settle into a pattern. DSs trouser size is always one year below his actual age. Tops correspond to his age.

I would normally say aged 2 is up to 2 so similar to 18-24. It varies massively though so depends on the brand. One 18-24 could be vastly different to another 18-24 from another shop.

Age 2 for example is up to about 2.

My DC is petite though and at 2 is still only just out of most 12-18, and is still in 12-18 for brands that come up bigger, with 18-24 stuff still falling down.

There's huge variance 🤷

Thanks for the responses!

@Namechangeymcnamechange11 yes I've found that my DD is still in 12-18 in H&M but has been in 18-24 in places such as GAP for a while.