![How To Make A Full Bust Adjustment to Princess Seams [with pictures]](http://weareleim.com/cdn/shop/articles/Untitled_design_3_2cdaf76b-130a-4d3b-a39d-d7babd2712f2_769x1024.jpg?v=1764159431)
Hellooooo, it's me, Hetty - the one who makes bathroom-friendly jumpsuits that you don't need to take off when you go to the loo.
The one who sells sewing patterns so that you can make those bathroom-friendly jumpsuits yourself at home.
The ones that makes bathroom-friendly jumpsuits with princess seams... OH.
Turns out, from my extensive research (on Instagram lol) that a lot of sewists find princess seams pretty daunting. I get it, adjusting them when you're kind of winging it is tricky, especially if you're like me and you don't like to toile...
But I am here to help you out. I have done a reckie of Full Bust Adjustment blog posts and 'how to' guides that are currently available on my first page of Google. And honestly, if I wasn't already very comfortable with how to do a full bust adjustment, I would probably be quite put off by them. So here I am, trying to make the process as uncomplicated as possible.
The pattern that I have used below is The Sisterhood ezp Jumpsuit pdf sewing pattern. It's my simplest style to adjust the bust of - I didn't want to make it too complicated, and this style has no back bodice, so it really is very simple. If you are considering another of my styles, just get in touch (hello @ we are leim.com) if you need some advice.
The style is drafted to a U.K. C cup with quite a high bust curve. If your cup size is above that, then you will need to do a Full Bust Adjustment (FBA) and potentially a waist adjustment too. Conveniently there are instructions on how to do both below, with pictures.
Strap in, let's go.
Finding the amount you need to increase the bust by
To do this you first need to find your high bust (HB) and full bust (FB) measurements - put your tape measure around the top of your chest, under your underarms to find the high bust measurement.
The full bust is the fullest part of your bust, usually around your nipple although not always.
Your FB measurement minus (-) your HB measurement is your cup size. Bras are measured in inches so I’ve used inches for this explanation - the rest of the pattern is in centimetres - sorry!
So if your HB measurement is 35" and your FB is 40", your difference is 5":
A cup - 1" difference
B cup - 2" difference
C cup - 3" difference
D cup - 4" difference
E cup - 5" difference
Therefore, your cup size would be a U.K. E cup.
Because this pattern is drafted to a C cup, we need to increase the bust measurement by 2" (from a C cup to an E cup).
Annotate your pattern
First step on your pattern - you want to mark the seam allowance (0.39"/10mm) on the pattern pieces. I like to trace a copy of the pattern piece (so keep the original clean) so I can go back to the original if I make any mistakes - saves printing it out again!
You also want to make sure you have clearly marked your grain line and notches - you will need these later!
I like to use different pen colours for different things (different lines / notches) but that's personal preference!
Next, we want to mark 3 points on the pattern piece:
- Cross 1 - At the Bust Apex, but on the seam allowance. There is already a notch here to guide you.
- Cross 2 - Perpendicular (at 90 degrees) to the grainline, from the Bust Apex cross to the seam allowance of the armscye. See image below:
- Cross 3 - 0.79"/2cm from the seam allowance at the top of the bust curve
Start drawing your cut lines
Draw line 1, a horizontal line from the Bust Apex to the armscye. This is shown in purple in the photo.
Draw line 2, from the Bust Apex to the upper cross. This is shown in orange in the photo.
Draw line 3, from the Bust Apex to the bottom of the pattern piece. It will be quite close to the bust curve edge of the pattern piece.
If you need to, bring the lower notch on the Bodice Side seam to join line 3 (you might not need to do that step, I haven’t had to here!) - you can see this in purple in the photo, right next to the green ‘3’.
Cut your lines... concentrate!
Okay we're going to take this slowly:
First, cut up line 3 and line 2, stopping at the cross. Don’t cut through!
Next, cut down line 1, but don’t cut through completely!
Then, cut the end of line 2, but don’t separate the 2 pieces. Leave a little hinge.
Now we are going to add in the space your full bust needs
So - we are going to separate the pattern pieces.
You want to move line 3 by the amount that you need to increase your bust by - for example, if you need to increase the bust size by 1 cup size, to a D cup, you will need to increase the space between line 3 and the rest of the Bodice Side piece by 1". In the example I have increased it by 2", to an E cup.
You will want to hinge the paper at the cross at the top of line 2 (in the seam allowance). Then you’ll be able to move the piece more easily.
I have placed a large piece of paper behind the pattern and taped the bottom of the Bodice Side piece to it. Then, I have marked yellow dots (see next page) in the bottom piece of paper. This is so I know where to continue the line of the bust curve.
Cut the notch on line 3, at the lower end of the Bodice Side piece. Tape this to the paper to mark the lower end of the new Bodice Side edge.
Don’t tape the spread area yet!
NOTE: If you don’t need to increase the waist area (check your measurements against the size chart), you can grade between the bottom of the new bust curve and the original waist of the pattern piece here. You may not need to do a waist adjustment, perhaps if you have more of an hourglass shape :)
Let's neaten things up a bit
Cut the rest of the paper away, marking the new pattern piece at the bottom of the pattern piece but keeping the area roughly around the top of the spread pattern pieces.
It’s hard to see in the photo above but if you squint a bit - to the bottom right of the pattern piece you can just see the tape of the bottom of line 3!
Mark along line 1 on the lower piece of paper, call this line 5 (marked in yellow). Cut this line, up to the point where it meets line 3.
Cut up to the point where lines 3 & 5 join, on the lower piece of paper. Don’t cut through to the other (already cut) half of line 5!
Join line 1 together again - bring the spread parts of the pattern down and tape Line 1 together again. This will create a dart where line 5 is:
Tape a piece of paper under the open part around line 5. Use your French Curve ruler to join the edge of the Bodice Side piece (shown in blue pen below)
Adjusting the length of the bodice
Measure the created space around line 5 (in yellow) and the space between the lower half of line 3 (the sliver of pattern piece we cut off before) and the area you cut it from before (again shown in yellow). Mine comes to +0.79"/2cm for the ‘dart’ and 1.8"/4.5cm for the lower area - the yellow pen isn’t so easy to read, sorry about that! But it’s for illustrative purposes anyway, yours will most likely be different.
We will add this added length to the Bodice Front piece. I will add 0.79"/2cm above the Bust Apex dart (shown in pink lines) and 1.8"/4.5cm above the lower waist dart (shown in green lines) - both on the Bodice Front pieces as below:
Adjusting the armscye shape
You might need to adjust the shape at the top of the armscye.
Now you can either trace around this pattern piece to have a clean copy.
Make sure to repeat these steps for your lining pieces too!
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I hope this guide helps - I found full bust adjustments soooo daunting when I started making the jumpsuits. I used to feel a little bit sick when I would see some measurements come in. But once you get your head around how the pattern works for your body, the world is your jumpsuit-flavoured oyster!
If you ever have any questions, please let me know.
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