If you have a light or regular flow, we recommend the Size A or Size Mini for teens or those who need a smaller size. However, if you have a heavier flow you might want to consider going with the Size B, which has a bigger capacity. Some OrganiCup users like to use a few different cup sizes throughout their cycle.Creative Woman:The Wizard of Bras -- Cup Size ChartCup Size Chart. To determine cup size, you subtract the band size from the bust measurement. The difference helps you calculate the cup size. Look at the graphic below the chart to help calculate your band size and bust measurement. One of the problems of being larger than a DD is that there is nothing uniform in cup sizing.