The Ngaio Blouse pattern comes with separate pattern pieces for Small (A-B), Medium (C-DD/E) & Large (F+) cup sizes.  This means it works for people with high and full bust differences from 2″-4″. If your high-full bust difference is more than 4″ (or you just find it a big snug across the bust), here’s how to do a Full Bust Adjustment (FBA) on the Ngaio Blouse. First, because I’m a massive nerd, and love explaining why things need to happen, rather than just telling people they do, here’s all the why’s behind FBAs and the Ngaio blouse. Why you might need an FBA The way I have you calculate cup size in the Ngaio Blouse pattern is to measure the difference between your full bust measure, and your high bust measure: The bigger the difference between your high bust and your full bust, the bigger your cup size. It’s a simple but effective system, but does have some drawbacks, because it’s only two measurements. I discuss this system, why it’s used, why it works, but …