When you take the right measures of your bra you will get a fitted bra with more feeling of comfort, it will make your clothes fit on your body and will make your style looks better.
Here I'll tell you how you can figure out your own bra dimensions.
1 - Relax while you are stands straight. Be normal and avoid inhaling to expand your rib cage.
2 - Use a simple tape measure to measure all around your body by placing the tape measure just beneath your breasts. Let us say - for example the measure is: 29 1/2.
3 - Add five to that number that you got it after rounding it up if necessary to the next even number. Now you got your band size, it's (35). Congratulations.
Now you will need to measure your bra's cup
To do that, wear a bra, and measure completely around the fullest part of your bust (across your nipple) without trying to pull it tight. Finally, Make sure the tape measure goes around your entire back (37).
Practical steps had finished! Now, subtract the number from your band size (37-35=2). The result will indicate your appropriate cup size, based on the following guide: