Buying a bra can be a true difficulty and take us away from the pleasure of shopping.
So how to be sure what size to buy?

Firstly it is important to know that bra sizes are not standard.

As you might have noticed from your previous shopping experiences, not 2 lingerie labels have the same fit. It is true as well as for the clothing brands.
So where to start when you want to buy a bra that fits you.

In general, the first thing you would like to check is your underbust measurement.
Take that measurement, right under the bust, when you exhale, arms along the body.
If your measurement is between 72 to 77cm you are a size 34US underbust or 90FR or 75Eu.
As per clothes, there is between 2 sizes, 5cm difference.
So if you are between 78 to 83cm you would be a size 36US or 95FR or 80EU.
Most lingerie brands would be following the same rules. Depending on the materials used for the back, you can get away with 1 size smaller or bigger in the case of a stretch back as you would be in a T-shirt.

The most important and difficult part is to select the right bra cup. By choosing the right band first, it makes it easier to select your bra cups.
You will have to take first into consideration the shape of your bra as well as the brand you are buying your lingerie from. Brands like Victoria Secret that targets a young public tends to fit smaller than a brand that is for more mature public (such as it would be on clothes).

The second thing you have also to know is that the cups are not the same throughout the different bra sizes.

A 32B is not the same cup size as a 34B. The cups are proportional to the band. In other word, if you would like to keep the same cup size but to have a wider underband, you will have to take 1 cup smaller, which means that a 32C has the same cup size as a 34B but the band would be longer allowing you more space at the rib cage level.
That being said, for the bigger cups size, this is not exactly true. For a cup size bigger than a C cup, the different between 1 cup size to the other is twice as big for smaller cup.
Between a cup B to C, there is 0.6cm all around the cup difference.
Between a cup C to D, there is instead 1.2cm.
So between a 34D and a 36C you will have the cup slightly bigger on the 36C than the 34D.
If you need so a bigger underband and slightly bigger cup, that is the size to take.

If you wish to know exactly your bra size, please contact me by email or chat. You will need to provide this last measurement: your nipple to rib cage measurement while wearing a non-padded bra. With this measurement and your underbust measurement (as explained above), I will let you know your precise bra size.