How to measure bra size?

[AngryFeet]

My underbust measurement is 39 and overbust is 45. On the online calcs it comes up as 44A. Really? I have quite big boobs

Bump

There was a thread or so about this recently and basically

1. old way of measuring under breasts and adding on 4 or 5 inches not right
2. measure under breasts - thus is your Bea size
3. same measurement on breasts you are an A, one inch bigger a B and so on. Nor sure when things like DD happwn as am 30C :)
4. try ones on in shops as ie 34a, 32b, 30c are same overall measurement and you need to find out which us best.

On your measurements I would say 38 or 40 back size and quite a big cup

Oh blimey! I thought the 36D i was wearing seemed a bit small . Better go and get measured properly then. So I am either 38G or 40E? Buggering hell.

From what I've read on here as well, M&S still use the measure under breasts and add on 4 or 5 inches type thing and people don't necessarily get well fitting bras there. Independent places can be good (I got my most recent bra at an independent shop and it's great. Not the cheapest ever but fits really well).

There are ways to tell with whether straps ride up or you get red marks that show how bra is too big/small but I find my brain getting confused at them