The cup size remains the same between 34D and 36D, as both are labeled "D." However, the difference lies in the band size; 36D has a larger band circumference than 34D. As a result, the overall fit and appearance can vary, with 36D generally providing a slightly fuller look due to the larger band size.
34d
34D
34D
34d
34D
34d
34D
34D
After 34D is 34DD. After 34DD is 34E. A chart and calculator is included in the related links below for you.
34D
34d & 38b.