To be honest, there isn't a distinctive conversion. Officially, the conversion for clothing is 2 sizes down, so you would be a 10 in the US, but my wife is from the US and she says that is not correct at all. Her view is it is more than 1 size down but not quite 2 sizes down.
My wife is a size 8.5-9 in the US and a 5.5-6 in the UK.
I'm a size 14 and a size 5.5 in shoe (but with wide feet) in the UK. In the US depending on the fit I'm usually a size 10. If the size 10 is on the neat side then a 12 is a bit roomy. I have some size 12 shorts I bought a couple of years back in the US when I was a bit more cuddly - I can take them up and down without undoing the zip/waistband now. It's just like here, you really have to try things on. We're just back and DD asked me to bring back clothes from American Eagle. She's a size 10 here and the American Eagle size 6 fit to perfection. Shoes - 8.5/9 again depending on the fit.
I think that is wrong, almost every conversion charts say 2 sizes down. In my DW experience having moved from the US to the UK, 2 sizes isn't accurate in reality either though.
I work in a Vintage clothes shop and it used to be one size down. Ie, a dress size 12 dress in the UK in 1992 would be a size 10 in the USA.
Now, they are generally two sizes different. Ie, a size 12 dress in the UK would be a size 8 in the USA.
I stress the word 'generally', as sizes differ in EVERY shop and are just there as a guide.
I think that is wrong, almost every conversion charts say 2 sizes down. In my DW experience having moved from the US to the UK, 2 sizes isn't accurate in reality either though.
You've really, really got to try stuff on. Use the chart as a starting point. I wear a size 8 in the UK but have several pairs of size 0 jeans and often buy "XS" items from the US, for example, which doesn't comply with any chart anywhere
However you look at it though, the number is smaller
I don't think I made my point very well... sorry! Most of the conversion charts say 2 sizes, others say 1 size down. My wife who is American says it's neither! My DW is a 16 UK and she's a US 12. The point I was trying to make (albeit badly) is that the conversions aren't definitive. My DW says it's 1.5 sizes down