Go down a back size = go up a cup size. e.g. a 36DD becomes a 34E. If you go up a back size but stay the same cup size, you'll notice extra room in the cup.
The difference is truly in the name… DD or DDD are the US standard; E and F are used more internationally.
The cup sizes A, B, C and D are the core ones. As you move up through alphabetical order DD would be one size larger than D. This pattern continues until you reach double-letter (like FF) cups which also have a gap of one between them; for instance, E is bigger than DD just like how DD is greater compared to D.
A 34E is the same as 34DD US.
Would an E cup be much bigger than a DD cup? - Quora. In the US a DD is the same as an E, but in the UK a E is the equivalent of a US DDD, and, if on the same band size, is one inch larger than a DD. (UK and US cups are the same from AA-DD).
The band size of 34 E is about 29 to 30 inches. The cup size of the bra is about 38 to 39 inches.
After size D you can either go up to size DD which is the bra size equivalent to size E, size DDD which is equivalent to size F, and size DDDD which is equivalent to size G.
0 = AA <1 = A 1 = B 2 = C 3 = D 4 = DD 5 = DDD/E 6 = F 7 = G 8 = H.
Large: 32D, 32DD, 34C, 34D, 34DD, 36C, 36D. X Large: 36D, 36DD, 38AA, 38A, 38B, 38C, 38D, 38DD, 40AA, 40A, 40B, 40C, 40D, 40DD.
The 36DD and the 38D are the same cup size, the only difference is the 38 band is bigger around then the 36 band.
There's no difference in the spacing between single and double letter sizes, a DD is one full size larger than D, just like E is one full size larger than DD.
In reality, the size difference between D and DD with same band size is 1”, the same measurement difference as between an A cup and a B cup, a B cup and a C cup, a C cup and a D cup.
So sure, a DD can be classed as a big cup size, but only if it's on a bigger band size too! And frankly, it's not even that big – the average US bra size is 36DDD and from experience, with more than 90% of the population wearing the wrong size, it could be that that is just the best-selling size.
The 34DD bra has a bigger band than the 32E bra. Even though the 34DD has much wider cups, the 32E has much deeper cups.
Proper cup fit is influenced by band size. As the band size changes, so does the cup size. For every band size you go down, you should go up one cup. If you are in a 34D with a good cup fit, but want to go down to a 32 band, you would go to a 32DD for a tighter band with the same cup fit.
In order to determine if your cup size is too big or small, look to see if you have an extra bump of breast tissue at the top or at the sides of the cups or if you have a wrinkle in the cups or extra space in the cup.
What is an E Cup in Centimeters? As we know above, an E cup breast means your overbust measurement is 5 inches larger than the ribcage measurement. In centimeters, an E cup should be 25 cm larger than your band size. Therefore, if your band is 60cm, your e cup bust size will be around 85cm.