In pattern making terms, a Full Bust Adjustment (FBA) is a modification that adds extra width and length over the bust area, so a garment fits a fuller bust without changing the fit at the shoulders, neckline, back, or waist. Instead of simply “sizing up” the entire pattern, you surgically add space where the body actually needs it, keeping the rest of the garment proportional and polished.

Most commercial patterns are drafted for a B-cup block, which means anyone with a fuller bust often sees drag lines, gaping armholes, pulling at the front opening, or a hem that hikes up in front.

Learn How to Pattern a Full Bust Adjustment

A torso sloper with a front side seam dart and back neck dart is used for a full bust adjustment. (Image credit: University of Fashion)

University of Fashion’s Full Bust Adjustment Lesson

Our Full Bust Adjustment lesson is taught by Martha Palaza, a fit expert who has conducted fit workshops throughout the Boston area. In her lesson for UoF, Martha demonstrates how to alter a torso sloper for a bust cup larger than a B, based on measurements from the ASTM Standard D8555-11 Body Measurements for an Adult Missy Figure Sizes- Size 00-20. She also demos how to increase from a C to a D to a DDD Cup. Martha’s Bust Cup Calculations & Cup Size Range Chart accompanies this lesson and provides key calculations & guidelines. (Image credit: University of Fashion)

Fabulous Fit’s Fitting System and how to use pads to increase the bust size for an FBA. (Image credit: University of Fashion)

Extracting key measurements from the dress form for an FBA: Bust Circumference, Under Bust Circumference, High Point Shoulder to Apex and Bust Span (apex to apex). (Image credit: University of Fashion)

Sectioning the front sloper in preparation for increasing the bust cup from a B to a C cup. (Image credit: University of Fashion)

Once you have recorded your measurements onto the Bust Cup Calculations & Cup Size Range Chart, you will learn how to section off requisite areas on the front sloper in preparation for increasing the bust and length areas of the sloper using the Cup Size Range Chart.

Testing the Full Bust Adjustment fitter made of muslin or test fabric. (Image credit: University of Fashion)

Once the bust cup adjustment sloper has been drafted, create a test muslin to check that: 1) there is enough ease at the side seam/armhole intersection, 2) there are no drag lines at the side seam, 3) the dart vanishes at the apex, 4) the waist dart aligns with the princess line, and 5) that the waist sits on the waistline and doesn’t ride up.

Mindset Shift: from “fixing flaws” to designing for reality

Learning how to pattern a Full Bust Adjustment isn’t just “fixing the bust.” It’s learning to draft for real bodies, reclaiming comfort and confidence, and stepping into true fit-engineer territory as a designer and maker. On a deeper level, learning to pattern an FBA is an act of inclusion. It acknowledges that “standard” bust proportions exclude a significant portion of women and femme-bodied people, especially plus-size and curvy sewists.

By teaching the FBA as a normal pattern adjustment rather than a “special problem,” we shift the narrative: bodies are not wrong; patterns are incomplete measurement—so the shoulders and upper chest fit—and then add the bust volume the pattern never accounted for. Learn how with Martha.