Bra size finder - the first thing to note is that accuracy really depends on how correctly you measure yourself. I used to buy bras at random too and often got my sizing wrong. But after this calculator was recommended to me, I decided it was worth a try. First, I took a centimeter tape and started measuring myself. It's important to do this in a relaxed environment, preferably in a bra that you feel comfortable in and without any extra clothing. The calculator prompted me to enter two basic measurements: under-breast girth and chest circumference. I followed the instructions strictly, and it wasn't as difficult as I thought it would be. When I entered my data, the calculator gave the size, and honestly, I was a little skeptical. Each manufacturer may interpret sizing a little differently, and I have sometimes encountered situations where the same model may sit differently depending on the material or construction.