Lower your arms. The measuring tape should be strictly horizontal and firmly pressed against your body. It will be more effective if you get someone else to measure you, but it is possible to do it on your own.
Put on the most comfortable and ordinary bra you have (not a push-up or a minimizer). The measuring tape should be stretched horizontally and pass over the point of furthest protrusion from the chest but without pressing down on it.
Table 1: work out your size using this table
Table 2: the difference between chest circumference and band circumference
Different countries use different systems to indicate cup sizes. If you want to buy underwear produced in a different country, use the following size comparison to work out what you need.
Table 3: Underwear size comparison for different countries
Our weight can change over time, yet many of us persist in buying the same bra size regardless of physical changes. Don’t wed yourself to one size. If your weight fluctuates by 3-5 kg, take your measurements again and look at different size options.
Now it’s time to go to the store. Bear in mind that trying on different bras until you find the right one may take around an hour and a half.