They should stay put without digging in. Remember: the band provides 80% of the support, not the straps. Pro Tip: The "Swoop and Scoop"
It should be level all the way around. If it arches up your back, the band is too big. You should be able to fit two fingers underneath it. how to buy correct bra size
Numbers are just a starting point; the mirror tells the truth. Look for these signs of a good fit: They should stay put without digging in
The center piece between the cups should sit flat against your breastbone. If it’s hovering, the cups are likely too small. If it arches up your back, the band is too big
If the number is even, add 0. If it’s odd, add 1. (Example: 31" becomes a 32 band). 2. Measure Your Cup Size
Wrap the tape loosely around the fullest part of your chest. Don’t pull it tight—just ensure it’s level all the way around.