BYC Clothing question

[Bantimna]

Yup, I'm considering buying some "My Pet Makes Me Breakfast" clothing, but I'm a little worried about sizes.

For the following Ladies sizes, what British Size would it be?

http://coopedup.net/buy/index.php?route=product/product&product_id=111

How Small is small?
How large is Medium?

Many Thanks!

ETA: Punctuation error

 

[DuckLady]

I found this converter . Hope it helps!

 

[Bantimna]

Thanks Terrie!