How to: Full Bust Adjustment


Want to adjust your bodice to fit your bust but don’t know where to start? Read our tutorial below on how to achieve a full bust adjustment for your bodice pattern.

*In this tutorial, we use the bodice pattern of the Peggy top as our example. The PDF pattern for Peggy is available here.

What is a Full Bust Adjustment? 

A full bust adjustment (FBA) is essentially making a bodice pattern bigger in the bust area, adding more space solely at the front in order to accommodate a larger bust. As most patterns are drafted on a B cup, you’ll likely need to do a FBA if, when looking at a standard measurement chart (such as the one pictured below), your bust measurement is in a larger size column than the rest of your body measurements. 

Working out your bust adjustment

To calculate how much (in cm) you need to increase your pattern by, you need the following four measurements:

  • Your waist measurement
  • Your hip measurement (at the fullest part)
  • Your high bust measurement, measured under your arms and across the very top of your bust
  • Your bust measurement at the fullest point of the bust 

When choosing what (standard) size to cut your pattern, choose the size based on your high bust measurement and then adjust it by increasing it by the difference between your high and full bust measurement. 

For example: let's say your high bust measurement is 96cm, and your full bust measurement is 100cm - the difference between the two measurements is 4cm.

When cutting your bodice pattern piece (such as the Peggy top as will be shown in this tutorial), you are cutting it on the fold and so the pattern piece is only half of the actual bodice. Thus, you need to half the difference between your high and full bust measurements, and increase the size of the pattern piece by this amount (in this case: 2cm).

Now you've got your measurements, it's time to alter your piece. Here is what you will need:

  • Tracing Paper
  • Pencil
  • Paper Scissors
  • Rectangular Quilters Rule

Step 1: 

Once you've cut out your bodice pattern to your preferred size, you need to mark the bust apex - this will be around the nipple. The easiest way to find this point is to hold up the pattern piece in front of your body, lining the fold line up at the centre of your chest. Make sure the shoulder part of the pattern is in line with your actual shoulder, and mark the apex of your bust with a pen.

Step 2:

Next, draw three lines from the apex point you have just marked:

  1. A vertical line parallel to the fold line that goes from the bust apex all the way down to the bottom
  2. A line from the apex to 1/3 way up where the armhole is
  3. A line from the centre of the side seam dart to the apex

Step 3:

Cut into your pattern paper along the first and second lines you have just drawn, stopping about a cm from the edge of the armhole curve in order to create a kind of hinge in the paper. 

Step 4:

Next, cut along the third line you drew, again stopping just before the edge to create a hinge.



Step 5:

Now place another piece of pattern paper underneath your cut out pattern, taping the bodice pattern down at the fold line.

Pull the left part of the pattern gently on the hinge (keeping the hinge intact) to create a gap between the left and right sides of the bodice where you cut the first vertical line.

Making sure that the distance between the two sides of the bodice is the same amount you worked out you needed to increase your bust measurement by (in our case, 2cm), tape everything in place.

Step 6:

Once you've taped everything down, you need to adjust your hemline as now the piece on the right side will be higher than the left. To do this, mark a straight, horizontal line across the right side somewhere along the bottom (it doesn't matter exactly where the line is) and cut along this line. Keeping it horizontally inline with the right side of the bodice, lower this section of paper so the bottom of it is level with the bottom of the left side of the bodice.

Step 7:

As the adjustments we have done have lowered the bust dart, we need to mark a new dart point. Mark it about 2.5cm away from the bust apex point, towards the left, and draw in the dart by drawing two lines from the original dart points to your newly marked dart point.

Step 8:

Mark a line through the centre of your newly created dart toward the bust apex.

Next, draw lines from each of your dart points so that they intersect this new dart line.

Step 9:

Finally, keeping everything stuck down, cut around your newly drawn pattern to create your final pattern piece. You have now done a full bust adjustment!

Want more tips + tricks? Read our Beginner's Guide to Cutting Woven Fabric here.

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