How to do a full bust adjustment without any darts

How to do a full bust adjustment without any darts

Posted by Helen | March 21, 2017 | Blackwood Cardigan, Sewing Tutorials
full bust adjustment no darts

full bust adjustment no darts

Today is the second post in a 2 part series on doing full bust adjustments on patterns without any darts.  For the first post, we covered a quick and dirty ‘pivot and slide’ method that works well for small full bust adjustments. Today, we will be covering how to do a proper slash and spread full bust adjustment, even when the pattern does not have any darts.

This post is part of a sewalong for the Blackwood Cardigan. You can grab your copy of the Blackwood here.

Do you need a full bust adjustment? The first thing we need to do is measure our high bust and our full bust. To measure the high bust, place the tape around your back, under your armpits, and across your chest ABOVE your breasts. To get your full bust, measure your bust across the fullest part of your chest. 

Next, find the bust measurement of the pattern you are working with. Choose your size based on your high bust measurement and do the following calculation:

Your full bust measurement minus the pattern bust measurement.

If the difference between the two measurements is more than 2”, you are a good candidate for a full bust adjustment (FBA).  The process can seem daunting, but trust me, learning how to do a FBA can be a total game changer for your sewing practice. You will be amazed at how much better things fit! 

Let’s get started!

Start by tracing your pattern piece onto a new sheet of paper. You want to keep the original pattern piece intact. You will need extra paper to fill in the gaps as we cut into our pattern for the FBA. Keep paper, pens, a ruler, and tape handy for this exercise. 

full bust adjustment no darts

Hold the pattern piece up to your body as close as you can to where it will sit when worn and mark where the ‘apex’ is (it’s right where your nipple is). Don’t fret about being 100% accurate, just eyeball it.

full bust adjustment no darts

Draw three lines. #1 from the apex to the side seam, roughly where a bust dart would be if there was one. #2 from the armscye to the apex and then straight down to the bottom, perpendicular to the bottom edge. #3 out to the front edge or center front fold line (depending on the type of pattern you are working with). The #3 line should be perpendicular to the #2 line and be about 2-4″ up from the bottom edge.  Again, just eyeball this to look like the picture below.

full bust adjustment no darts

Cut line #2 from the bottom, stopping 3/8″ from the edge (or however much the seam allowance is on your pattern). This is indicated by the black dot in the diagram below. You may need to cut into the seam allowance from the edge to get a smooth pivot point here, or you can simply create a small fold. Cut line #1, leaving a small bit of paper intact where line #1 meets line #2 if possible (again, this is for pivoting). Completely cut through line #3. This is called ‘slashing’.  Now, ‘spread’ the pieces out as in the diagram below.

full bust adjustment no darts

You want to focus your attention on the width of the gap in line #2. This width should be half of the difference between your full bust measurement and the pattern bust measurement.

For example, if I have a difference of 3”, I divide that by 2 to get 1.5”. The gap in #2 should measure 1.5″ for me.

full bust adjustment no darts

Place paper under your pattern piece and measure the gap before securing it in place. the two sides of line #2 should always be parallel. Once taped down, your new dart will fall into place and you can move the little piece from slashing line #3 down to true up the bottom edge of the pattern. Tape these all down onto more paper, filling in the gaps. Trim of excess paper.

full bust adjustment no darts

Now you have a dart-like shape, but it is not pointing at the right spot. It needs to be re-drawn to point to the apex. Using a pen and ruler, re-draw the dart to point at the apex mark (shown as line #4 in teal below).

full bust adjustment no darts

OK! We have a pretty great start here, but you are probably wondering – why do we have a dart? Isn’t the whole point to not have any darts?  Well, that depends. Darts can help get a great fit through the bust. They might be uncommon in RTW knit garments, that that doesn’t mean you can’t have them! If you want to keep the dart, all you need to do is ‘back off’ the dart point 1-2″ from the apex. You also need to add a dart hat. If you want to get rid of the dart, skip down to the next step.

If making the Blackwood Cardigan, you should adjust the front and bottom band. Add the same amount of length to the front band as you did to the front of the bodice. Add the same amount of width to the bottom band as you did to the bottom of the bodice.

We had to create the dart in order to make the adjustment, and now we are going to redistribute the excess fabric in that dart in order to eliminate it.

Slash open your new dart by cutting it out completely or cutting one edge so you can rotate it.

full bust adjustment no darts

Cut along the inner side of the original #2 line to the apex mark. Try to leave a little paper for pivoting here. Rotate the side piece out to close the dart. Tape it shut. Buh-bye dart!

full bust adjustment no darts

Fill in the new gap with paper and leave some extra paper on the side for the next steps.

full bust adjustment no darts

Now we have a huge waist dart. We need to get rid of this. Using the gap in the dart as a guide, draw a new dart with the point near the bottom of the armscye. Slash open the left leg, leaving a bit of paper.

Close the dart by swinging the lower right portion of the pattern over. Tape closed.

Blend down from the side seam to the hem.

If you are making the Blackwood Cardigan, you should adjust the front band. Add the same amount of length to the front band as you did to the front of the bodice.

See? That wasn’t too complicated, was it?  I know it is a lot of paper and cutting and lines and what not, but once you do one, you will love the results. Soon, FBA’s will be second nature to you!

Remember to also check out the ‘pivot and slide’ FBA method as well. You may find that is all you need!

Blog Comments

Thank you for your two part tutorial!! I have been recently scouring Pinterest and Google for these very adjustments. While a found a few that are similar, you have explained these two techniques more clearly and concisely than any that I was able to find by far! This will be very helpful to me and I’ll be referring back on a regular basis.

Excellent post for the bigger busted. Thank you very much. I wrote a post recently on how to do a FBA on a wrap top (Gertie for Butterick B6285) here http://plumage.me.uk/2017/03/full-bust-adjustment-on-wrap-top-butterick-b6285-by-gertie/ which hopefully is also helpful!

Thanks, Deborah! I love how many awesome resources are out there now, this is awesome 🙂

I think I finally understand FBA’s.
I have read other blog posts, but your diagrams and explanations are great. Thanks for this excellent reference.

Thank you Asheley! That is really nice to hear 🙂

You have the best graphics. I did an FBA this same way on my Greenwood tanks and it worked perfectly. Definitely worth the extra effort. 😉

I am just wondering, you mention since you have a 3″ difference, you split that by 2″ to get 1.5″. However, doesn’t the pattern already include a 2″ difference, so why is it not 3″-2″ = 1″ and divide the 1″ in half, to get a gap of 0.5″ per side?? My other question is, do you work with the pattern piece from your over bust size? (so overbust plus 2″ to find full bust piece to alter). Any help is appreciated 🙂 Trying to fully understand FBAs…

I have the same question as Kristen – wouldn’t you subtract out the 2″ difference already accounted for, then divide the difference in half? Thanks! This is a great tutorial!!!

Hi Helen.
Your post was the best I have come across, so I don’t suppose you would be able to do one on a princess line dress would you? PLEEEEEEASE! XXX

[…] has a helpful, step-by-step, illustrated tutorial for the wide/broad shoulder adjustment and a full bust adjustment without darts. I followed Alexandra Morgan’s video tutorial for doing a broad (or narrow) back adjustment. The […]

[…] (FBA). If the difference is more than 4”,  you may want to skip this quick method and try a full-on FBA.  That said, given that we are working with knits and this pattern is designed to be open at the […]

My difference is exactly 2” so which method do I use?

I would try the quick method first!

I must be doing something wrong, but when I compare my new pattern piece with the FBA, it’s exactly the same width across at the bust as the old pattern! I am assuming it’s something with the cutting and then folding on top over… I assume that is not the intended outcome?

I am sewing V1415, the front is all one piece. I’m assuming I just do the same thing on both sides?

Yep, exactly!

Leave a Reply

Related Posts

Posted by chloe | 02 May 2019
Hi friends! It’s Chloe again with another sustainable scrap-busting project! If you’re just tuning in, I’ve started a blog series all about how to use your fabric scraps to make...
Snap Front York Pinafore Hack
Posted by helen | 16 April 2019
I can’t get enough of hacking the York Pinafore! This pattern is just so much fun to play around with and I still have loads of ideas for hacks. Today...
Posted by chloe | 11 April 2019
Hello friends! Chloe here. I am very excited to debut my new blog post series, all about ways to practice sustainability in sewing. Sustainability is always at the front of...