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Fitting Commercial Patterns - FBA

Saturday, April 09, 2016
Fitting Commercial Patterns is a very popular workshop for home sewers and textile teachers.  This week I've been going all-out to improve the workbook materials for this workshop in preparation for some professional development training I'm delivering in Melbourne next week to the Victorian VET textile teachers.  I've decided to share a section of that new workbook in this post, covering the Full Bust Adjustment (FBA) on an existing shirt pattern.Fitting Commercial Sewing Patterns

The shirt pattern in question has no bust dart included in the pattern.  So for anyone with a cup size greater the B you'll need an FBA alteration to create a better fit and a more balanced garment.

Locate  your Bust Point on the Pattern

Bring the front and back shoulder seam together to find the original shoulder line as marked by the pattern company.  Fortunately in most cases pattern companies leave enough information on each pattern to find the important parts of the pattern for alteration (i.e. shoulder lines, waist level and hip level, etc.). 
  •  Measure straight down from the original neck point of the shoulder line toward the bust area to mark the Front length to Bust Level. 
  •  Square across from the Centre Front (CF) line for half the Bust Separation to find the exact Bust Point.
  • Extend these lines, so they run in four directions from the bust point; toward the hem and the side seam.
  • Cut your pattern into four pieces ready for the pattern alteration.  
  • In this example I'll be using craft paper to distinguish the original pattern from the alteration and I'll be adding 1.25cm (½") in front length and the same in bust circumference.
  • Using the CF as a stable balance line for the placement of pattern pieces: begin by gluing down the top right section of the pattern.
  • Mark a new line 1.25cm (½") from the bottom of this pattern piece to add the extra length required over the bust.  Match and glue the bottom right side pattern piece along the CF line.
  • Keep the shoulder seam together, angle the top left pattern piece 1.25cm (½") from the BP.  this move adds extra width in the front pattern across the bust area.
  • And finally, keeping the hem together, angle the bottom left pattern piece to include an extra 1.25cm (½") at the BP.
  • All of these alterations have resulted in extra length on our front side seam.  You'll turn this extra length into a bust dart.
  • Measure 3cm away from the BP, along the new dart area, to mark the start point for the stitching line for your dart.
  • Join this new point to the outside edges of the extra fabric on the side seam to form a bust dart.  These are the stitching lines for your dart.
Finishing the bust dart in your sewing pattern.
Although these pattern alterations are not as exciting as creating new patterns, they are so valuable in our understanding of fit and how we can constantly improve the patterns in our stash.  Let me know if you have any questions, I'm always happy to help. :)

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BeccaA commented on 10-Apr-2016 01:33 AM
Thank you for this clear explanation of the FBA. My problem is that I need to narrow the shoulders while creating an FBA. Can you explain how to combine the two alterations?
Anita - studiofaro commented on 11-Apr-2016 10:28 AM
Hi Becca, thanks for dropping by. Yes I think you can do a narrow shoulder alteration with the FBA. How do you usually alter the shoulders of your patterns?
Pat commented on 14-Apr-2016 01:40 AM
That is the most logical FBA I've ever seen; it makes so much sense. Thanks for posting it. Would love to see how you do an FBA for princess seams.
Kay commented on 14-Apr-2016 04:07 AM
You've explained this so well and the pictures really help- thank you!
Anita - studiofaro commented on 18-Apr-2016 10:09 AM
Thank you Pat, that's music to this teachers ears. :) I'm working on other alterations so stay tuned for those princess seam alts.
Anita - studiofaro commented on 18-Apr-2016 10:11 AM
My pleasure Kay. :) It's good to hear when that these posts hit the spot.
Jill commented on 23-Oct-2016 05:10 AM
You added 1/2" in each direction at the bust point. What measurements were used to make that determination? How would I know how much to add for my own FBA?
Anita - studiofaro commented on 23-Oct-2016 04:00 PM
Hi Jill thanks for dropping by. In this post I've used ½" as an example only. The addition of ½' across the bust is equal to one cup size up in industry grading. Everybody will have different needs and you can only make the assessment from the first fitting of the pattern. As you get more experience you'll work out the best amount for your own patterns and be able to apply it to every pattern you use.

If you can give me more detail about your measurements and usual fitting experience I may be able to work out for you how much is needed in your alteration.
Anita - studiofaro commented on 06-Mar-2017 06:39 PM
Hi Marion Thanks for getting in touch. :) So much depends on the drafting system you're using.  If it allows for different calculations including the bust and chest measurements then maybe you would be able to make this adjustment at the drafting stage. In most cases it's something you have to adjust after drafting.  Which drafting system are you using? Anita
Anonymous commented on 06-Mar-2017 06:45 PM
Thank you Anita for your very quick reply. 

I draw my bodice block using pencil and cardboard .

By your reply it seems that I can draw the bust dart bigger than the normal 2" for a "B" cup.

This would then give me a block with the cup alteration built in, saving time later on. 

Incidentally it took me ages to work out why my skirts never looked right.  The answer was that my hip line is 7" below my waist and not 9" as found in so many commercial patterns!  Proportion is everything!!!

Thank you very much for your answer and for your terrific website.

I would imagine there would be a good market in supplying blocks made up by using a client's own measurements.  I am 70 and a bit old to contemplate such a venture but I am sure someone could start up that type of business!

Anita - studiofaro commented on 07-Mar-2017 11:01 AM
Hi Marion, thanks for bringing your comments onto the blog. :)

Yes, proportion is everything in pattern making. We need all the curves on the pattern to be in the same place as the curves on our body.

If you drafting system permits you to make the dart bigger then it's best to do that in the beginning. Please be sure to also check that your centre back length to waist is also accurate so you don't get too much fabric pooling above the waist in the back bodice.

Your suggestion for personalised blocks is a good idea but largely a complex process requiring personal attention to each clients measurements. The more technically savvy may be able to produce a bit of software that ensures accuracy in fit using individual body measurements. My pattern making work is largely manual and I'm also at the latter end of my career and not really that interested in chasing such a big piece of work. I believe there are some companies out there claiming they can produce individual blocks but the results I've seem are not all that useful. I'm sure there will be many systems in the future that will be able to cater to that market.

Let me know how you go with your block and remember I'm always here to answer any of your questions. :)
Ceridwen commented on 29-Dec-2018 02:39 AM
I’m currently trying to do a FBA for Butterick 6554 (a wrap dress with raglan flutter sleeves) when I have a 6” difference between high bust and full bust - the reason I had to learn to sew! This is always the most time consuming part of the project, as many of the bodice styles are a long way from a plain bodice block. I will try this method to see if it is more elegant than trying to hide all of the huge dart/s generated by the traditional method. Can I do it without resorting to pleats and gathers, I wonder...
Anita - Studiofaro commented on 29-Dec-2018 01:59 PM
Hi Ceridwen, thanks for getting in touch. Yes, I agree an FBA on a wrap dress is quite the challenge. And the extra large dart is mostly unavoidable to get the shape required. Sometimes it can be hidden/disguised in other features in the dress. I'd love to help more and can do so in my Facebook group. If you're willing to post photo's of the pattern front we can chat about the best solutions for that particular style. You'll find me here: https://www.facebook.com/groups/studiofaromakers/
Anonymous commented on 13-Oct-2020 10:26 AM
I have problems with hip measurements. Skirt always too tight.
Anita - Studio Faro commented on 16-Oct-2020 02:34 PM
Thanks for dropping by. With hip measurement I always add at least 4-6cm garment ease extra to my body measurement. That way I have plenty to play with when I'm fitting my pattern and getting balance between the front and back.

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All images, designs, photos and layouts on this blog are created and owned by Anita McAdam© of Studio Faro. They are available FOR HOME AND PERSONAL USE ONLY.  If you would like to use our content for teaching or commercial purposes please ask.  I have some amazing resources for teachers and manufacturers. ;) enquiries@studiofaro.com

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