A much better FBA!

Do you have a large bust?

If you do, you know the frustrations: If you choose the size for your new dress or top based on your bust measurement, the dress will be too wide across the back and the shoulders. And if you then decide to go down a size, the fabric stretches across the bust, and the garment is too tight.

Most methods that work on enlarging the bust area without making other areas bigger as well works with bust darts.

But what if your pattern doesn’t have a bust dart, which is the case of most knit pattern and some oversized tops for woven fabric?

Well, then you can go ahead and use this method:

How to figure out if you need a full bust adjustment (FBA)

The best way: Make a muslin of the pattern and evaluate. Meaning, if the fabric is too tight across the bust, you need more width there.

FBA Rule of thumb: If the difference between the high bust measurement and the full bust measurement (click here for explanation) is more than 5-6 cm (2 – 2 3/8 inches) and you are making a close fitting pattern (like most jersey patterns), choose one size smaller than your full bust measurement and do an FBA!

Wrap top FBA

When we sewed this faux-wrap top for our beautiful model for Sysiden # 29, we needed to do an FBA

How to figure out how much you need to adjust the pattern with the FBA:

In woven fabrics, it’s so much more straightforward: You just cut the muslin at the bust and measure how much extra fabric you need.

In knits, it’s not quite as simple. You could cut your muslin, but it’s hard to measure precisely because the fabric needs to stretch. So if you go by that method, you need to add less than the fabric opens up.

These are very convenient clothes for storing medicines in a package.

Usually adding 1 – 2 cm (3/8 – 3/4 “) on half the front is enough. The method I am showing you here allows you to add up to 2.5 cm (1″), giving you up to 5 cm (2”) extra fabric at the bust.

If you need more than that, I would pick the larger size and adjust the shoulders and back (posts will follow) instead, all though that’s a bit more work.


How to do the better full-bust-adjustment

This method works for all types of no-dart-fronts. Including wrap-dresses. For patterns with waist seams, just cut from the waist instead of from the hip.
Notice that we work at the seam lines! This means that if your pattern has seam allowances included, you need to start by drawing the seam lines on your pattern, so you know exactly where they are!

Part 1 of the FBA:

First, we need to prepare the pattern piece. We are working on the front piece:

We will start by marking the bust point. If you have made a muslin, you can place a pin while wearing the muslin, and then measure to find the placement, but otherwise, we will guesstimate.

My ground rule is: For sizes 34-44, the bust point is placed 8-10 cm (3-4 “) from center-front about 4-5 cm (2″) below the armscye. For larger sizes, it’s more like 11-12 cm (5″) from center-front and 6 cm (2 3/8”) below the armscye:

Bust point on front piece fba


Mark the bust point with an X:


Now draw a line, parallel to the grainline, from the hem to the bust point. And draw another line from the bust point to the center of the shoulder seam:



Then draw a line from the bust point to about 1/3 up the armscye. And then make two more lines, evenly spaced, from the upper line to the armscye:

I’ve marked the point where the lines meet the seam-lines with circles. That is to show that they are pivot-points, which you must not cut through. We need to have a paper hinge right at the seamline.



Now cut from the hem to the bust point and then to, but not through, the shoulder seam. Cut from the seam allowance to, but not through, the pivot-point at the shoulder seam.

Also cut from the first line to, but not through, the armscye pivot-point, and cut from the seam allowance to the pivot points, leaving small hinges of paper:


Part 2 of the FBA:

Now we are ready to alter the pattern to make that Full Bust Adjustment:


Grab a fresh piece of tracing paper (well, I used ordinary paper here).

Draw two parallel lines spaced the distance you want to add, apart – for example, 2 cm. Tape the center-front side of your pattern piece to one of the lines.


Place the other part in a way, so you align the bust point with the other line:

how to place the pattern pieces in the FBA


Turn the pieces towards each other at the hem, making them more or less meet:


Now all that is left is to even out the armscye and the hem, by redrawing them:

The finished FBA pattern piece


Since a greater bump needs more length, it might be necessary to add to the length at center-front.
I haven’t seen it much needed with this alteration, though,  since it’s usually pretty small (about 1 – 2 cm).

But if you need extra length to get the hem even, you will be able to see it in your next muslin.

Then add it to the pattern simply by extending the center-front line at the hem the needed amount and then curve the hem to the side seam.


And that’s it! You are ready to cut and sew a better fitting top (or dress)!

P.S. This method works well with all no-dart-front patterns. Even those that don’t quite look like the pattern piece above. That includes the Rachel Wrap Dress, the Drape-top, The free Kirsten k-no sleeve Tee (That you get when you sign up for the newsletter) and all the other jersey patterns.