Full Bust Adjustment or FBA Tutorial: Adjusting Waist Darted Bodice

Today I’m going to show you how to make a full bust adjustment on a dress bodice pattern with one waist dart. I’ll be using Jessica’s Stepford Dress pattern to make the pattern adjustments on, but the technique applies to any darted bodice.

With the exception of Colette Patterns, which seem to be drafted to fit C and D cups, most women’s sewing patterns are drafted for a B cup. Which makes sense, because dress forms have B cups. And hopefully, most patterns are draped on a form to perfect fit, before being transferred to a paper pattern.

If you are larger than a B cup, you may find your dress bodices and top projects riding up in the center, or being too short waisted. They might also  just be a little too tight around the bust. Pulling forward of the armhole is a telltale sign.

You may be tempted to buy a pattern in the size of your full bust measurement in order for the pattern to fit, but that’s a mistake. The bodice or top will then be too big in the back, shoulders, and armholes. I would recommend you always buy a pattern to your high bust or high chest measurement if you are over a B cup, and instead, do a full bust adjustment to the bust area for better results.

For instance, I usually buy a size 12 pattern . My measurements are 37- 28.5- 37. So If I bought a pattern in my bust size it would be a size 16. It would fit my bust and it would be huge everywhere else.  I buy patterns based on my upper bust which is 33.5 inches. And I do a FBA.

Here’s how I adjusted the Stepford Dress pattern to fit me. Hopefully this tutorial will smooth the path for your FBA learning journey or odyssey! It took me awhile to get the hang of the FBA but I’ve done them enough now to feel confident enough to share how I do it/. This post was originally on The Sewing Rabbitt where I write a monthly blog post.

The technique of adjusting the one darted bodice goes like this: Slash through the dart up to the apex and then to the armhole; Open pattern extra width needed; Rebalance the pattern by adding a side dart.

FBA needed.

First, I always make a muslin of dress tops and shirts. I only sew up the basic pattern pieces and don’t add any other sewing details. This helps check the fit. You have to do the FBA to the pattern before you cut the fabric so this step is a must and will save a lot of heartache , not to mention action for your seam ripper. As you can see from my muslin of The Stepford Dress above the bust is way too small. But how do I know how much bigger I should make the pattern ?

You will need to measure the difference between your full bust and the measurement on the pattern. Since my full bust is 37 and the pattern is a 34 I need to increase my pattern by 3 inches. BUT, I’m only working on half my pattern here, so I need to open my pattern up 1 1/2 inches. So: Find the difference between your full bust and the pattern’s measurement and cut it in half,

First patch the dart on the pattern so you have a space to draw a line through the center.

This pattern had a cutout dart so I had to patch it first.

Note where your apex or bust point is on your muslin and mark it on the pattern. If you are an indie pattern designer, PLEASE include your apex point on your patterns. It makes life much easier for people who have to do an FBA. And always include your center front line. Just my two cents here.Draw a straight line from the center of the dart to the apex. Draw another line from the apex into the armhole.Cut through the lines from the waist to the armhole but not all the way through the armhole. Open the pattern until the opening at the apex is as wide as you need. I opened my pattern up 1.5 inches. The difference between the pattern’s measurement and mine but cut in half because I’m only doing one side of the pattern. Do you see how the dart looks so crooked from the bottom? I need to make the opening going down parallel all the way from the apex to the waist to have a balanced waist. Also, at this point my dart will be way too huge, as well as unbalanced, so I need to add a side dart to the pattern to allow some of that extra room in the dart to move over to the side dart.Draw a line from the side seam to the apex but not all the way through it. Open the line and magically a side dart will appear! Adjust the opening until the opening of the front dart area on the pattern is the same size all the way down tot the waist. Parallel Lines. Any of you old enough to remember the punk new wave singer Blondie? Her album Parallel Lines was my favorite back in sixth grade! Back to the subject at hand… or bust..

Here is an important thing to notice at this point. The left side of the pattern is now LONGER than the right side. What the? Don’t worry.That’s the amount of length that needed to be added to the length. So not only did I make the pattern longer to allow more room for a bigger bust and avoid a short waist, but it’s wider in the center, too. But due to the dart being at the side seam the side seam won’t be longer the side seam at the back of the pattern. When I fits started sewing dresses for me, I would add width to the side seam and then wonder why the fit was terrible. Has that happened to you?Patch the pattern from behind.Cut out the new dart. Hopefully that should do the trick!

Corrected muslin.