This refers to UK bra sizes, other countries' sizes may be different.

The sizing system for bras consists of a number, which is the band size (underbust) in inches, and a letter, which is the cup size (based on bust measurement.) Band sizes go up
in incraments of 2 inches, cup sizes go up in incraments of 1 inch.

To calculate bra size:

1 - measure underbust in inches
2 - round this measurement up to the nearest even number. This is your band size
3 - measure bustline in inches (wearing a well-supporting bra)
4 - round this measurement up to the nearest whole number
5 - work out the difference between the 2 numbers
6 - for every inch difference, go up a cup size, as follows:

less than 1 inch - AA
1 inch - A
2 inches - B
3 inches - C
4 inches - D
5 inches - DD
6 inches - E
7 inches - F
8 inches - FF
9 inches - G

If the size you get from this method is too tight, go up a band size and down a cup size.

eg underbust measures 31 inches, bust measures 37 inches.
Bra size should be 32DD, but if this is too tight, a 34D may fit better.

Cup size is relative - a 32DD is much smaller than, say, a 36DD. 36DD is equivalent to 34E, which is the same as 32F.

Fitting tips:

A new bra should fit on the BIGGEST adjustment to allow for stretch over time. If it already fits comfortably on the smallest adjustment, go down a band size (and up a cup size to compensate)

If you have uneven cup sizes, go with the bigger side.

It's better to buy a new bra when on your period, you're often bigger then.

The band of the bra should be horizontal and not ride up at the back: If you pull the shoulder straps upwards, the band should gently grip your back. If it slides up easily, the band size is too big.

If the top edge of the cups make a double bulge, or you feel squashed inside them, the cup size is too small.

If the shoulder straps dig in and leave red marks, they are either adjusted too short or they're taking too much weight. The weight should be taken by the band, so you may be wearing a band size which is too big. Similarly, if you find you keep having to shorten the shoulder straps, try going down a band size instead.

You should be able to run a couple of fingers around inside the band. If you can stretch the bra out from your chest or fit your whole hand under the band, it is too loose.
Many women wear the wrong bra size
by Zoggi1 June 19, 2006
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A-Almost boobs
B-Barely boobs
C-Can't complain
D-Dang
DD-Double Dang
E-Enormous
F-Fake
G-Get a reduction
H-How bad are your back problems?
I-Is that even possible?
Guy:Dude, what was that chicks bra size?

Guy 2: I dunno... all i could think as she walked past was Double Dang!
by Demioteka April 1, 2009
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The size of a girl's lady parts, the letter coded sizes have different meanings:

A - Awkward
B - Basic
C - Comfortable
D - Decent
DD - Delightfully Decent (Damn)
E - Enourmous
F - Fake
G - Gasp
Girl 1: Hey Tracy, I've always been wondering, what's your bra size?
Girl 2: I'm a size C but I don't really mind, I guess I'm comfortable with it..
Girl 1: At least you're not a size B like me, my boobs are pretty basic boobs i suppose, I wish they were bigger.. O_o
Girl 2: I know what you mean, I wish I could be a size D, that's pretty decent if you ask me:)
Girl 1: Haha, look on the bright side, at least you're not an A..That would be so awkward to live with haha..
by Jemina110 June 18, 2013
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Levels of general ability (intelligence) that are way below average; literally, IQ scores between 32 and 40, the typical range of bra sizes excluding cup size.
North Alabama has always had a goverance problem due to the bra-size IQs and general venality of public officeholders.
by Princess Lum November 27, 2005
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A, B, C, D, E, or F --- can you tell a girl's high-school report-card grade by da cup-size of her "upstairs undergarment"? Are gals with bigger boobs often less intellectually-capable? Dunno. But maybe da chicks with da smaller fun-bubbles hafta be smarter in order to get ahead in da financial world, 'cuz they don't get so many guys who are willing to spend money on them just to be allowed "touchy-feely" privileges!
his whole "test scores vs. bra-size" thing puzzles me... if da size of a woman's boobs are in direct inverse proportion to her intelligence, why do gals wif huge chests get da lion's share of da gifts and attention from neighborhood guys, and lustful employers choose to hire Dolly Partons over flatter-chested chicks???
by QuacksO March 26, 2019
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What my grandmother told me every time I complained about something that was unfair.
If life was fair there would only be one bra size.
by awmm February 23, 2021
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Bra sizes:
A - Almost boobs
B - Barely Boobs
C - Can't complain
D - Dang
DD - Double Dang
E - Enormous
F - Fake
G - Get a reduction
H - Help me I've fallen over
She has a bra size A which means almost boobs.
by Skycyclonex November 21, 2021
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