You need to measure your chest size. Follow the list below:
If your chest size is between 86 and 89; then the appropriate dress size is small (mini).
If your chest size is between 91 and 96; then the appropriate dress size is medium (midi).
If your chest size is between 97 and 99; then the appropriate dress size is large.
If your chest size is between 102 and 104; then the appropriate dress size is extra large. ​