To check your bra size, you need only take two measurements which are :
     
  Step One - RIB SIZE MEASUREMENT  
     
 
Measure around your rib cage directly underneath the bust, holding the measuring tape straight around the body.
 
     
 
Enter the result in inches here :
 
     
     
  Step Two - BUST SIZE MEASUREMENT  
     
 
Measure completely around the fullest part of the bust, holding the measuring tape straight around the body.
 
     
 
Enter the result in inches here :