Tutorial: How to make a full bust adjustment on a bodice without underarm or side seam darts

TUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTSTUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTS • Workroom Social - Sewing studio in Brooklyn, NY

Tutorial: How to make a full bust adjustment on a bodice without underarm or side seam darts

TUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTSTUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTS • Workroom Social - Sewing studio in Brooklyn, NY

Now that you know two different ways to choose your sewing pattern size, I want to walk you through a full bust adjustment (F.B.A.) on the Tate Top. This same method can be applied to any bodice without underarm or side seam darts. (I’ll also talk about using the same method on a bodice with underarm darts at the end of the post.)

For this tutorial, I used the measurements of Dress Form B from the How to choose the right sewing pattern size tutorial. To recap, I chose a size 12 for Dress Form B instead of a size 16 based on her high bust measurement (Method 2), and now we need to do an F.B.A. on the pattern so Dress Form B will have enough room across her bust for a well-fitting top.

Things you need to make a full bust adjustment (F.B.A.)

table of contents

#1. Determine how much you need to add for your full bust adjustment
#2. Prep the pattern by marking the alteration lines
#3. Prepare to make the full bust adjustment by cutting the pattern alteration lines
#4. Add width to bodice to make the full bust adjustment
#5. Make a dart in the side seam to create the fitted silhouette of the original pattern
#6. True the hemline
#7. Use this method for a bodice with underarm or side seam darts
#8. Quick note about dart manipulation
#9. Additional F.B.A. tutorials and resources

#1. Determine how much you need to add for your full bust adjustment

Use your high bust measurement to select your sewing pattern size. For this tutorial I modified a size 12 for Dress Form B.

To determine how much you need to add for the full bust adjustment, start by finding the difference between the final bust measurement on the bodice (sewing pattern) and your bust measurement with desired ease (human body).

Dress Form B bust + 1″ ease
41″ minus ->

Final garment bust measurement
38.5″ ->

Difference (amount to add for the F.B.A.)
= 2 1/2″

Because we will only alter half of the front bodice (right side only, not both left and right sides), take the F.B.A. amount (2 1/2″ in this example) and divide it in half. Our F.B.A. amount for the alteration is 1 1/4″.

#2. Prep the pattern by marking the alteration lines

Before we start any cutting and moving things around, we need to draw in some lines to help us know where to add room for the full bust adjustment.

TUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTSTUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTS • Workroom Social - Sewing studio in Brooklyn, NY
Click on the image to enlarge it!
  • Cut out the front bodice pattern piece. If you are using the Tate Top, cut the front bodice in half down the center front line. We are only going to alter half the pattern.
    Quick tip: Only print what you need! For the right half of the Tate Top bodice only, print pages 1, 2, 5, and 6 for the cropped top. Add pages 9 and 10 for the tunic length.
  • Start by marking your bust apex on the pattern piece. Some patterns may come with the bust apex already marked. You can use that, or mark your own along the bust level. The Tate Top includes the bust level, but you will need to determine the precise position of your apex along this line. On your body, measure the distance from your bust apex to center front. Then transfer this distance onto your pattern piece. The bust apex will likely be somewhere between 3 1/2 to 4 1/2 inches from the center front.
  • Draw a line parallel to the bodice center front/straight of grain from the bust apex to the hemline. Let’s call this Line A.
  • Draw a second line from the bust apex to the armhole, somewhere in the bottom half to bottom third of the armhole. There is no exact measurement for this position. Just do your best to copy the image above. This is Line B.
  • Draw a third line from the bust apex to the side seam, somewhere around 2″ below the armhole. Again, the exact position of this line isn’t important. You don’t need to measure exactly 2″ below. Just somewhere around there. This is Line C.
  • Finally, mark a short portion of the armhole seam line where it intersects with line B. While you could mark the entire seam line around the armhole, it’s not necessary.
  • Double check to make sure your final marked pattern looks like the example above.

#3. Prepare to make the full bust adjustment by cutting the pattern alteration lines

TUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTSTUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTS • Workroom Social - Sewing studio in Brooklyn, NY
Click on the image to enlarge it!
  • Starting at the hem cut along Line A, stopping at the bust apex. At the bust apex continue cutting along Line B, stopping just before reaching the armhole seam line.
  • Starting at the armhole this time, cut along Line B again stopping right before the armhole seam line. It’s just a little snip from the armhole to the seam line. Do your best to not cut through the armhole seam line. The tiny un-snipped portion will act as a pivot point when spreading the bodice.
  • Your front bodice piece is now cut in half (though hanging together by that little piece of paper at the armhole seam line). Let’s call the half closest to center front the center bodice, and let’s call the half closest to the side seam the side bodice.

#4. Add width to bodice to make the full bust adjustment

TUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTSTUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTS • Workroom Social - Sewing studio in Brooklyn, NY
Click on the image to enlarge it!
  • On a scrap of paper, draw two parallel lines separated by half the full bust adjustment width (1 1/4″ in this example as explained in Step #1). These lines will act as a guide when spreading the pattern along slashed alteration lines. Let’s call this paper your width guide.
  • Place the width guide behind the slashed front bodice piece. Align the slashed Line A on your center bodice with right side of your width guide as shown above. Tape the slashed pattern to the width guide along Line A and Line B on your center bodice. Don’t tape the side bodice down just yet.
  • Spread and rotate the side bodice (still hanging on by that little piece of uncut paper) so that the bust apex corner touches the left line of width guide. Once aligned, tape the side bodice to your width guide along line B only.

#5. Make a dart in the side seam to create the fitted silhouette of the original pattern

TUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTSTUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTS • Workroom Social - Sewing studio in Brooklyn, NY
Click on the image to enlarge it!
  • Starting at the side seam cut along Line B stopping just before the apex. Like we did with the armhole, we want to create a little paper hinge to keep the pattern piece together.
  • Spread Line C to align the Side Bodice Line A with with the left side of your width guide. Tape down Line A. We’ve successfully added the 1 1/4″ F.B.A. amount to our bodice pattern, and you’ll also notice that we just created a dart!
  • To make this new dart sit well on your body, we’ll need to redraw the dart legs to point back to the bust apex point. Right now they are kind of pointing down. To do redraw the dart legs, connect each dart opening at the side seam back to the original bust apex.
TUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTSTUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTS • Workroom Social - Sewing studio in Brooklyn, NY
Click on the image to enlarge it!
  • Next, to get rid of any pointy-boob situations, we need to pull back the end of the dart so it stops before the bust apex point. To do this, find the center of the dart by bringing the dart legs together and folding the paper to crease the center of the dart. Along the center of the dart, measure and mark 1 1/2″ to 2″ from the bust apex. This is the final dart apex point. Again, redraw the dart legs from the side seam to the new final dart apex point.
  • The last thing to do to finalize your new side seam dart is to mark the dart jog. The dart jog is the outward or inward pointing triangle that you find at the dart opening. Sometimes the jog will point in towards your garment, while other times, the jog will point out, depending on the shape of your dart and how your dart intake is meant to be pressed. We will press our darts down towards the waist, creating an outward triangle at the dart opening. To mark the dart jog, again fold your pattern piece along bottom dart leg, and bring it to the top dart leg.
    Quick tip: When the dart is folded closed the pattern piece changes from 2D to 3D, which can make it difficult to work with. Before you start folding the bottom dart leg, fold the pattern piece back on itself at the dart apex. Now when you fold the bottom dart leg and bring it to the top dart leg the pattern will lie flat.
  • With the dart closed, draw in your new side seam blending from the top of the side seam at the the underarm to the bottom of the side seam at the hem. You are now ready to mark the dart jog. Using a tracing wheel, a thumb tack, or a pin, poke holes along the side seam making sure to poke through all layers of the paper pattern. Open the dart and see the final marked jog! Cut along new side seam and dart opening (along the pin holes) for the final side seam of your newly altered pattern.

#6. True the hemline

We’re almost done! Just one step left. Let’s finish the hemline.

TUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTSTUTORIAL: HOW TO MAKE A FULL BUST ADJUSTMENT ON A BODICE WITHOUT UNDERARM OR SIDE SEAM DARTS • Workroom Social - Sewing studio in Brooklyn, NY
Click on the image to enlarge it!
  • Somewhere kind of near the hem draw a line from center front to Line A that is perpendicular to center front. Let’s call this Line D.
  • Cut along Line D from center front stopping at width guide. If the bodice is taped to the width guide below Line D, cut down Line A to the hem to separate this little rectangular shape. If the bodice is not taped below Line D, the little rectangle should just fall off. Let’s call this little rectangle the center front hem.
  • Slide the center front hem piece down until the full hemline blends together nicely. You can just eyeball the exact placement. Do be sure to keep the center front line straight and on grain.
  • Tape everything in place, adding paper to the pattern where you have gaps.
  • Blend the final hemline together using a ruler or just freehand it!
  • Your final F.B.A. altered pattern piece should look something like the above.

#7. Use this method for a bodice with underarm or side seam darts

You can apply this same tutorial to a bodice with an underarm or side seam dart. The only difference is that instead of eyeballing the placement of Line C, you will want to draw line C to end at the center of the side seam dart (at the side seam).

#8. Quick note about dart manipulation

The original Tate Top does not have a side seam dart, but that doesn’t mean it can’t. The original pattern was drafted for a B-cup, which allowed us to create the roundness in the shirt with only the neckline dart. If have a larger bust, adding the side seam dart allows you to keep the close-fitting silhouette of the Tate Top in a woven fabric. The garment in the end has the same visual shape as the original, and it will fit you way better!

If you prefer, however, you can rotate the side seam dart created by the F.B.A. back into the neckline dart if you are only adding a small amount for the alteration (maybe 1/2″ on either side or 1″ total F.B.A.).

#9. Additional F.B.A. tutorials and resources

Need more encouragement before you try your own F.B.A.? Read more about full bust adjustments and all the various ways you can add more room for the ladies up front.

  • Great timing, I have been planning to add an FBA to a dartless bodice for my mum and wasn’t sure how to go about it. Thank you fo such a clear and helpful explanation.

    • I hope it’s helpful! Writing out the explanation my eyes went a little cross-eyed. It’s a lot to take in as a reader! Good luck!

  • Lety

    Fantastic! I’m a DD and really struggle with FBAs where there isn’t a dart. Thanks for making it so clear! Phew!

  • so glad i just saw this. i finally have the perfect fabric for my top but was hesitant because i knew i was gonn have to FBA it. xx

  • Emily D

    Hands down the best FBA walk through I’ve ever read. On a related note, what is the best way to remove the additional space created at the waistline? My full bust is 44 but my waist is 35 and I like enhancing the hourglass shape ????

    • Hi Emily! Glad this tutorial was helpful. If you’re doing an FBA on a dress bodice that needs to keep its waist size, you can shave off a little from the side seams. Start at nothing at the underarm and gradually create that hourglass shape, narrowing as you approach the waistline. Hope that makes sense!

  • Wow those instructions are awesome!

  • Pingback: Women’s Blake Dress | Sew Shelly Sew()

  • Dina P

    Awesome tutorial! Really easy to follow and understand.

  • Lisalu

    I followed every step of this tutorial and ended up with a hot mess. Yes, I successfully added depth to allow for a full bust and added a dart. But there is nothing here to explain how to adjust the armscye after adding that side dart. After my first attempt, I found that the opening was too tight. On my second attempt, I folded the dart into place on the altered pattern piece, then redrew the armscye to follow the original pattern (and I did the same with the side seam.) This was even worse, because when I sewed the resulting front bodice to the back bodice, it didn’t hang correctly, everything was out of whack. Spent a lot of time, fabric, tape, and tracing paper just for it to end up in a wad on my sewing room floor. 🙁