Full Bust Adjustment
Your pattern pulls across the bust or the side darts don't lie flat? You probably need a Full Bust Adjustment. Enter your high bust and full bust measurements — we'll calculate the exact slash-and-spread amount for your pattern type.
How the darted FBA works
Commercial sewing patterns are drafted for a B cup — a bust measuring about 2 inches larger than the high bust. If your cup is C or above, the front bodice will be too small, causing pulling, gaping buttons, or a hemline that rides up.
The darted FBA adds width to the front piece using a slash-and-spread technique: two cuts are made through the bust point and the piece is opened by the FBA amount, creating a new side dart. The back, sleeves, and collar are unchanged. Pattern size is set by your high bust, not full bust.
How to take these measurements
High Bust
Wrap the tape directly under your armpits, above the bust. Keep it parallel to the floor, snug but not tight. This sets your pattern size.
Full Bust
Wrap the tape at the fullest part of your bust, parallel to the floor. Wear a well-fitting, non-padded bra. Don't compress — the tape should rest against your body. This sets your adjustment amount.
Related tools
Same FBA calculation for princess-seam patterns — spread the side front without darts.
Excess fabric at the bust? Calculate the overlap amount for A cup and smaller.
Is your pattern too tight or too loose? Compare your body to the pattern to check ease by fit style.
Enter bust, waist, and hip — find your size across 11 brands with size charts. Sewing sizes ≠ store sizes.