Full and Small Bust Adjustment

1886 Corset Advertisement Do you struggle to fit commercial patterns because the bust always seems to be too small or too big? Have you tried taking it up a size, found yourself spending ages altering all the other seams, and finally discovered that the fit is totally off? Then you may need to perform a bust adjustment.

The Full Bust Adjustment (FBA) and Small Bust Adjustment (SBA) are ways of enlarging or reducing the breast area of a pattern only, without altering any other area. It is suitable for patterns with a princess seam construction at the point of the breast - in other words, seams that run vertically over the bust with no bust gussets.

A Full Bust Adjustment

Before performing an FBA be sure to check the following:

1. The breast is positioned correctly – see the article "Fitting The Bustline"
2. The corset is correctly fitted at the sides, back and waist – often "squished boob syndrome" can be attributed to poor fitting in these areas.
3. Remove bras if they contain padding or enhancements which will not be present while wearing the corset.

Your front panel pieces will look something like this (right):

Performing A Full Bust Adjustment

To avoid getting bogged down in Maths, I will perform a one inch FBA. (In other words, I've measured my pattern and discovered that the bust needs to be 2" bigger around the front to accommodate the client's measurements - 1" bigger over each breast.)

Bear in mind that this technique can accommodate much larger increments too.


1. Transfer design of the front panel pieces on to graph paper; make sure you include all markings. If you are altering your own pattern, create corresponding notches just above the widest point of the bust curve to help fit the pieces together later. Ignore the indicated grain line on the pattern and line up the panels so that the curves are parallel to the side of the paper. This will make the next step easier:	2. Alter the pattern piece with the more pronounced curve first. Find the widest point of the curve and mark where this starts and stops.

3. Make a note of how wide this gap is and how far away it is from the triangle:	4. Divide the required expansion by 2 and increase the widest point of the curve by this amount. In this example the required extension is 1 inch, so the widest point of the bust needs to be increased by half an inch.

5. Taper the increase to join the original seam line:	You can use the original pattern to assist you in getting the right shape:

6. Next we adjust the second pattern piece. Use the measurements taken in step 3 to mark the corresponding section:	7. Draw a horizontal line at the midway point between these lines:

8. Cut along this line and spread the pieces to extend the panel by the amount you added to the other panel piece - in this example it is half an inch. 9. And that, surprisingly enough, is it!

Small Bust Adjustment (SBA)

An SBA is a way of reducing the breast area of a pattern without altering any other area.

It is suitable for patterns with a princess seam construction at the point of the breast - in other words, seams that run vertically over the bust with no bust gussets.

Before performing an SBA be sure to check the following:

Your front panel pieces will look something like this:

Performing A Small Bust Adjustment

To avoid getting bogged down in Maths, I will perform a one inch SBA. (In other words, I've measured my pattern and discovered that the bust needs to be 2" smaller around the front to accommodate the client's measurements - 1" smaller over each breast.)

Bear in mind that this technique can accommodate much larger reductions.


1. Transfer design of the front panel pieces on to graph paper; make sure you include all markings. If you are altering your own pattern, create corresponding notches just above the widest point of the bust curve to help fit the pieces together later. Ignore the indicated grain line on the pattern and line up the panels so that the curves are parallel to the side of the paper. This will make the next step easier:	2. Alter the pattern piece with the pronounced curved first. Find the widest point of the curve and mark where this starts and stops. Make a note of how wide this gap is and how far away it is from the triangle:

3. Divide the required reduction by 2 and reduce the widest point of the curve by this amount. In this example the required reduction is 1 inch, so the widest point of the bust needs to be reduced by half an inch:	4. Taper the reduction to join the original seam line. You can use the original pattern to assist you in getting the right shape.

5. Now we adjust the second pattern piece. Use the measurements taken in step 2 to mark the corresponding section:	6. Normally we would draw a horizontal line through the centre of the marks which correspond to the widest point, cut along this line and then overlap the pieces to shorten the panel. However, if we did this in this case (illustrated above) then the horizontal cutting line would not reach the end of the panel. So what we do instead is to lower the top of the panel by the amount we reduced the curve on the other panel (in this example by ½ inch). 7. And that, surprisingly enough, is it!