You need two measurements to get an accurate bra size.
1. Underbust Measurement
Measure under your bust.
If your measurement is an odd number add 5 inches. (Example: 31 inches measured = 36 bra size).
If your measurement is an even number add 4 inches. (Example: 30 inches measured = 34 bra size).
2. Overbust Measurement
Measure round the fullest part of your bust to determine cup size.
Be careful that the tape is not too tight, it should just be sitting across your bust comfortably.
Using the underbust measurement find your cup size by following the guide below.
If your overbust measurement is:
Same as underbust size = Cup size A (UK/Aus), Cup size AA (US)
Under 1 inch = Cup size AA (UK/Aus), Cup size A (US)
1 inch over = Cup size B (Universal)
2 inches over = Cup size C (Universal)
3 inches over = Cup size D (Universal)
4 inches over = Cup size DD (Universal)
5 inches over = Cup size E (UK/Aus), Cup size DDD/E/F (US)
6 inches over = Cup size F (UK/Aus), Cup size DDDD/F/G (US)
7 inches over = Cup size FF (UK/Aus), Cup size G/H/J (US)
8 inches over = Cup size G (UK/Aus), Cup size I/J/K (US)
9 inches over = Cup size GG (UK/Aus), Cup size J (US)
10 inches over = Cup size H (UK/Aus), Cup size K (US)
11 inches over = Cup size HH (UK/Aus), Cup size L (US)
Example: Underbust measures 31 inches. Over bust measures 33 inches. Your bra size would be a 36C.
Please note: Larger sizes do vary!
Always check to find out from the stockist what measurement they are using.
In the US many manufacturers add inches to the underbust measurement sizes, called ‘vanity sizing’, this can be 4, 5 or even 6 inches.
In the UK some brands do have their own sizing system. Marks and Spencer leave out FF and HH, so their J size is equal to the cup size H (UK). ASDA cup size H is equal to cup size G.
How should the bra look and feel?
There should be no bulging at the top or sides of the cups. Importantly it should feel comfortable. If it is an undewire bra, the wire should lie against the rib cage. The back of the bra should be level all the way round, in line with the front. For fuller busts, a three pronged clasp is more supportive. The straps should not dig in and should be parrallel with each other.
Move your arms around whilst trying the bra. If you can feel any digging or see any bulging it would be a good idea to try a bigger size.
Not every bra conforms to your actual measurements. It is always best to try before you buy.