How to do a FBA or SBA for a Raglan Sleeve Top

Here are step-by-step instructions for doing a Fuller Bust Adjustment (FBA) or Smaller Bust Adjustment (SBA) for a raglan-style top.  

Making pattern adjustments may seem a bit daunting at first, but the effort is completely worth it to achieve a beautiful, handmade garment with a custom fit.  After you've practiced a few times and figured out what adjustments work best for your body, it will become second nature.  

Materials

Gather some basic materials to adjust the pattern pieces:
  • Top Front pattern piece (we're using the Pixie Duffel)
  • measuring tape
  • scrap paper
  • tape
  • ruler
  • pen/pencil
  • scissors

 

Measure

To determine the size of adjustment necessary, measure your high bust and full bust. 

The high bust measurement is taken around the body, with the tape snugged up to the underarms, and above the breasts. 

The bust measurement is taken around the fullest part of the breasts.  

Measuring High Bust and Full Bust for FBA SBA for Fable Dress by Twig and Tale

Compare your body measurements to the size chart (click here to view, or it can be found in the pattern tutorial).  

For example:
  Size H Your body measurement
High Bust measurement 34" (86cm) 34" (86cm)
Full Bust measurement 36" (91cm) 38" (96cm)
In this example, the full bust is 2" (5cm) larger than the size chart, so an FBA is needed.  
Pattern adjustments will be made to half of the garment (because the pattern piece is cut on fold), so you will add half of the 2" (5cm) difference = 1" (2.5cm).  

 

Bust Apex

The bust apex is marked on the pattern.  It is a good idea to measure your own bust apex to make sure the bust dart ends up in the correct position for your body. 

To find your bust apex, measure from the curve where your shoulder meets your neck (imagine the position where a shoulder seam line would sit against your neck) to the centre of your bust - this is the part that points out the most.  Note that the bust apex is not necessarily the same as your nipple position.  We recommend taking this measurement while wearing your favourite underwear.

How to do a FBA or SBA for a Raglan Sleeve Top by Twig + Tale

Check your measurement against the pattern.

Fuller/Smaller Bust Adjustment (FBA/SBA) for a Raglan Sleeve Top by Twig + Tale

Keep a note of the difference between your bust position versus the pattern. For example:

 Pattern = 9.8" (25cm)
Your Bust Position = 11.8" (30cm)
Difference = 2" (5cm)

 

Full/Small Bust Adjustment

Adjust pattern pieces

1.  Begin by drawing cut lines on the Front pattern piece as follows:

  • Line parallel to Centre Front (CF) from the hem to the end of the dart (line a on diagram below).   
  • Line at right angles to CF from the dart end to CF line (line b on diagram). 
  • Line through centre of dart to dart point (line c on diagram).
  • Line from dart end to stitch line of armhole seam (line d on diagram). 

 

2.  Cut the pattern along lines a-d, keeping the pivot points intact at the dart end and armhole seam allowance (see diagram for location of pivot points).  If you accidentally snip through the pivot point, use some tape to create a hinge.  

How to do a Full Bust Adjustment for a Raglan Sleeve Top

3.  Be sure to mark the original dart end so you don't lose it in the changes. This is VERY important. 

Fuller/Smaller Bust Adjustment (FBA/SBA) for a Raglan Sleeve Top by Twig + Tale

For the following steps, it is a good idea to position your pattern piece over a larger piece of paper, so that once the adjustments are made, you can cut around the entire finished piece.  This will prevent the pieces from shifting around.  

4.  Secure the top section of the pattern piece with tape, then draw a line extending the CF edge below the pattern piece. 

Fuller/Smaller Bust Adjustment (FBA/SBA) for a Raglan Sleeve Top by Twig + Tale

Now, apply your full bust difference to the pattern.  In our example, the full bust difference is 2" (5cm).  Divide the difference in half: for example 2" (5cm) / 2 = 1" (2.5cm) because we are working on half of the front piece.

Slide the side section over by your calculated difference: our example is 1" (2.5cm).  Let the dart and armhole pivot - the side will move down and the dart will open.  For an SBA, slide the pattern piece in, so that the dart closes and the cut section overlaps.

Fuller/Smaller Bust Adjustment (FBA/SBA) for a Raglan Sleeve Top by Twig + Tale

5. Slide the centre section down by 1/2" (1.25m), along the CF line you drew earlier.  For an SBA, slide the centre section up.

How to do a FBA or SBA for a Raglan Sleeve Top by Twig + Tale

6. Redraw the dart stitching lines so that they meet at the point of the original dart end (note that for a Small Bust Adjustment, the dart end may slide underneath the pattern piece).

How to do a FBA or SBA for a Raglan Sleeve Top by Twig + Tale

7. Blend the hem and smooth the armhole if needed. 

How to do a FBA or SBA for a Raglan Sleeve Top by Twig + Tale

You may choose to create a cutout in your dart if the dart ends up too wide at the side seam. 

Fuller/Smaller Bust Adjustment (FBA/SBA) for a Raglan Sleeve Top by Twig + Tale

8. The adjustment is now complete; however, if your Bust Point is different to the pattern, we'll continue below with a few more steps.  

Fuller/Smaller Bust Adjustment (FBA/SBA) for a Raglan Sleeve Top by Twig + Tale

 

Modifying the Bust Apex

The dart should be positioned so that it points directly towards the Bust Apex.  It may be necessary to move the dart up or down so that it is positioned correctly.

8. Cut two lines at right angles to the Centre Front Line. Above and below the new dart. 

How to do a FBA or SBA for a Raglan Sleeve Top by Twig + Tale

9. Slide the darted section down or up by the difference.  In the example above, we calculated the difference as 2" (5cm) lower, so we will slide the piece down by that amount.

Fuller/Smaller Bust Adjustment (FBA/SBA) for a Raglan Sleeve Top by Twig + Tale

10. Blend the side seam on both sections.

Fuller/Smaller Bust Adjustment (FBA/SBA) for a Raglan Sleeve Top by Twig + Tale

 

11. Your pattern piece is now ready to use!

Fuller/Smaller Bust Adjustment (FBA/SBA) for a Raglan Sleeve Top by Twig + Tale 

If you have any questions about sewing or making adjustments, please feel free to join us at the Twig + Tale Facebook group.