The Uk and the US use the same inches to determine the band size but not entirely the same for cup size besides A-B-C-D-DD cup size.
The chart below will show you where the two countries’ bra size starts to change, which is pretty easy to read and understand the difference in bra sizing.
Bra size conversion uk to us chart
This chart makes it easy for you to figure out UK bra size into US bra size.
UK & US band size
The UK and the US band size are the same as shown in the chart below. These two countries carry the same band sizes.