How do you do a Full Bust Adjustment, an FBA, when the pattern has no bust dart ? This tutorial shows two approaches: a slash-and-spread FBA that adds fullness without introducing a dart, and an alternative method that adds a side-seam bust dart for a fuller bust. It also explains how to choose your size using your high bust measurement, mark your bust point, and check the fit with a toile so the shoulder and neckline stay balanced.
The Rochester sewing pattern has no bust dart and a gathered neck, so how does one go about doing a full bust adjustment (FBA for short) to add a little more room where one may, ahem, require it??
It’s not that tricky, just slash and spread! I’ve got 2 methods for you to try, the first is shows how to add extra without adding a bust dart. The second method is pretty much a standard FBA and adds a bust dart at the side seam. You may find the dart helps to give a nicer fit if you have a bigger bust and need to do a very large FBA.
*As this is our 3rd FBA tutorial you may already know the theory and how much to add for your FBA. If so, scroll on down to the Method and miss out the next bit which is the same as the FRENCH DART FBA tutorial.
What is a Full Bust Adjustment (FBA)?
Sewing patterns are generally (and there are exceptions) drafted to accommodate a B cup. All Maven Patterns are drafted with a B cup. Unfair I know, but unfortunately, it’s just not possible for us to produce a pattern that will keep all body shapes happy, as we are all unique and the variations are limitless.
So, great if you are a B cup, but not so much if you are bigger (or smaller). In which case you might need to do a Full Bust Adjustment – FBA (or a Small Bust Adjustment – SBA). An FBA is a pattern alteration that will put a little more room in the bust area to accommodate a fuller bust should you need it, and if we are going to go to the trouble of making our clothes, might as well make them fit as well as we can.
SIZE UPDATE: We now have The Rochester available in a D cup in sizes 18-32 as part of our MAVEN 1832 range.
Can’t I just go up a size?
You can, but the pattern will then most likely be too big across your shoulders and your back. What you need is more width and length in your pattern at the right place – to go over and around a fuller cup. The idea of the FBA is to do this without messing about with your armhole and sleeve and keeping a great fit in the shoulder.
How do you know if you need a full bust adjustment?
Your toile may be gaping at the armhole, will have drag lines pointing to the bust, and probably looks a bit ‘strained’ over the bust, your boobage just looks a little squashed in there!
Small Bust Adjustment side note: A SBA is basically the same process, but involves overlapping the pattern to reduce instead of spreading the pattern to increase the bust cup size. If you need a Small Bust Adjustment, there will be too much fabric over the bust area, and your bodice will be too long at the centre front.
Abbreviations
FBA / full bust adjustment SBA / small bust adjustment CF / centre front BP / bust point/apex
Equipment
- Copy of pattern (or the ability to re-print)
- Ruler
- Pencil
- Sticky tape
- Tape measure
- Paper scissors
- Pattern paper
Which cup size are you?
Measure yourself while wearing the appropriate underwear. If you are going to wear a padded bra under your dress, go put one on first – it will make a difference to the fit.
Importantly, your cup size for a sewing pattern is not the same as your bra cup size. (I’m a B for a pattern, and wear a D bra)
- Measure your HIGH bust across your back, under your armpits and above your bust.
- Then measure your FULL bust, at the fullest part of your bust.
- Note these measurements and the difference between them.
- Difference of 1” (2.5cm) = A cup (SBA)
- Difference of 2″ (5cm) = B cup
- Difference of 3” (6.5cm) = C cup (FBA)
- Difference of 4” (10cm) = D cup (FBA)
- Difference of 5” (12.5cm) = DD cup (FBA)
Pick your size
If you are above a B cup you’ll probably need to do an FBA and should select your size by using your HIGH bust measurement in place of your FULL bust measurement.
This is the most common and popular method, by far, because it will give a better fit in the shoulders and neck area, then you just do a Full Bust Adjustment and alter for a fuller bust. If, on the size chart, you have a size 16 full bust, but a high bust measurement of a size 12, chances are the shoulders of a size 16 pattern will be completely out of proportion for you! You may still need to adjust or blend between sizes for hips and waist.
How much to add?
It’s a bit of chicken and egg situation. There is not one way to do this alteration (or any alteration). It can be a little test and see, and a lot of getting to know your OWN body and how you like a garment to fit on you. Take these measurements as a guide. If you start googling this, you’ll find a lot of different advice and it’s not that any of it will be wrong – just different ways work for different bodies, garments and preferences. You just have to start somewhere to find what works for you! You’ll need to toile and test and tweak your alteration, maybe more than once. A toile is going to be your best friend – the fabric doesn’t lie! Also, consider the look of the garment, a looser fitting garment might not need as much adding as a very fitted garment. Or you might just decide you want more/less ease and adjust your FBA accordingly.
I’ve got 2 options listed below: Either toile and slash open to give an idea, or a bit of Maths. It is very much trial and error the first couple of times until you know what works for you.
TOILE: Make a quick toile (just the body, don’t bother with sleeves, collar etc). Try it on and mark your bust point. Cut a cross in the fabric at your Bust Point / Apex, let it spread open and then measure how much extra you need. (For a SBA, instead of slashing, pin the excess out of the bust)
I like this slash and spread and see-what-you-need method. Pay attention to the neck and shoulders of your toile, and see if they fit or if a size smaller/bigger would look better on you.
MATHS OPTION: Take your FULL bust measurement and minus your HIGH bust measurement = TOTAL FBAamount to add. DIVIDE TOTAL by 2 = the actual amount to be added to pattern (Remember when you are adjusting the pattern you are working with HALF a body front so you’ll need to divide the total amount of extra needed by 2 before adding to your pattern).
METHOD / Full Bust Adjustment
FBA without a bust dart
This method is taken from Fast Fit and Sewing Patterns , combined with a bit of ‘Y’ dart method from Fit for Real People.
- Find the Bust Point (also called the APEX) The Bust Point (BP) or Apex is already marked on The Rochester pattern for you so it’s very easy to find (you’re welcome!). Mark your BP on the pattern and compare with the BP that has been pre-marked on the pattern. If there is a lot of difference, use your BP for the alteration as you want the extra to sit in the right area for your bust. (How to find your BP – Lower a bust dart tutorial)
Draw the Lines
- Using a copy of your front pattern, mark the seam allowances so you know where the stitch line is.
- LINE 1: Draw a line from the BUST POINT (BP) right down to the hem, parallel with the CENTRE FRONT LINE. Draw a line from the BP to a point about a ⅓ of the way along the armhole.
- LINE 2: Draw a line from the BP to the centre of the shoulder.
- LINE 3: Draw a line from the BP to the midpoint of the neckline.
- LINES 4 & 5: Draw 2 lines from armhole to line 2 spread evenly between the shoulder and line 1.
Cut the Lines
- Cut along LINE 1. Start at the hem and cut to the BP and then to the armhole. Cut UP TO stitch line but NOT through it. Cut from OUTSIDE of the pattern up to the same point on the armhole stitch line, leaving a 3mm hinge of paper.
- *If you hinge your armhole from the outside edge of the pattern instead of the stitch line, your armhole increases in length and then your sleeve won’t fit.
- Cut along LINE 2 leaving a hinge at the shoulder stitch line.
- Cut along LINE 3 leaving a hinge at the neckline stitch line.
- Cut along LINES 4 & 5 leaving a hinge at the armhole stitch line.
- Mark sections A, B, C & D as in the diagram below.
Slash & spread
Place some paper behind your pattern pieces. Draw a line on your paper (shown in red). Anchor down section A with tape or pins, lining up the pattern CF with the one you just drew. Draw a couple of lines to show the amount being added (the orange lines), keep them parallel with CF. Draw a line to show where half the amount being added is.
Open LINE 1 out the amount you need to add for your FBA, pivoting the pattern from the hinges at the armhole and shoulder. Section B BP moves out half the total amount needed. Keep SECTION D parallel the with CF and allow to move outward so the full amount needed is added. Let front sections slide into position and overlap sections C to allow the pattern to open wider and stay flat. Note how the hem is staggered and the SECTION D is now too short.
Tape everything down and redraw the hem and shoulder seam and smooth the armhole curve. Redraw your front facing so it is the same shape as the altered neckline. Toile to check your alteration.
If you find the above method doesn’t work for you, you may find it necessary to add a bust dart for a better fit.
FBA – Adding a bust dart
- Find the Bust Point (also called the APEX) | The Bust Point (BP) or Apex is already marked on The Rochester pattern for you. As this style doesn’t have a bust dart, compare your BP with the pre-marked pattern one. The BP is going to move and drop anyway during your alteration. The FBA will make the dart drop around ¼” to ½” (6mm – 12mm) and if it’s too high we can adjust this later once the dart has been added. If you are very low busted (the BP needs to be lower more than 1.5” / 3.8cm), lower it a little now, and then go back and get it perfect later. You’re going to need a toile to check the final position when you’ve completed the FBA.
GOOD TO KNOW
- Your BP is the most prominent point of your boob – usually the nipple.
- Bust darts point towards the BP but the dart tip is set back so not to create a pointy end.
- B cup patterns usually have the dart tip set back 1″ (2.5cm) from the BP, but you can adjust this to suit you.
Draw the Lines
- Using a copy of your front pattern, mark the seam allowances so you know where the stitch line is.
- LINE 1: Draw a line from the BUST POINT (BP) right down to the hem, parallel with the CENTRE FRONT LINE. Draw a line from the BP to a point about a ⅓ of the way along the armhole.
- LINE 2: Draw a line from the BP to the side seam – this will be your dart (you can adjust the exact position later if necessary)
- LINE 3: Draw at a right angle from CF to intersect with LINE 1 (not crucial where).
Cut the Lines
- Cut along LINE 1. Start at the hem and cut to the BP and then to the armhole. Cut UP TO stitch line but NOT through it. Cut from OUTSIDE of the pattern up to the same point on the armhole stitch line, leaving a 3mm hinge of paper.
- *If you hinge your armhole from the outside edge of the pattern instead of the stitch line, your armhole increases in length and then your sleeve won’t fit.
- Cut along LINE 2 through the centre of bust dart towards the BP, leaving a hinge at BP.
- Mark sections A, B, C & D as in the diagram below.
Slash & spread
Place some paper behind your pattern pieces. Draw a line on your paper (shown in red). Anchor down section A and D with tape or pins (bear in mind, D will have to move again), lining up the pattern CF with the one you just drew. Draw a couple of lines to show the amount being added (the orange lines), keep them parallel with CF.
Open LINE 1 out the amount you need to add for your FBA, pivoting the pattern from the hinges at the armhole and BP. Keep SECTION C parallel the with CF. Let front section slide upwards and allow the bust dart to open wider to keep pattern flat.
Note how the hem is staggered and CF is now too short. Tape section A, B & C down.
Cut open line 3, no need to leave a hinge this time. Keep CF in line and slide section D down so the hem is level again and tape.
Tape everything down and redraw the bust dart and shoulder seam and smooth the armhole curve.
True the bust dart. Draw the new bust dart legs. Remember, the tip of a bust dart is usually 1” (2.5cm) from the BP, but this can change depending on you – it could be ½” (1.2cm) if you are small busted and up to 3” (7.5cm) if you have a fuller bust. Fold your dart, along the dart legs as if you are stitching your dart closed, with the excess downwards. A bit of tape doesn’t go amiss to hold the dart temporarily in place. (Now is the time to go excess upwards if that is your preference). While the dart is still folded, use a tracing wheel along the side seam of the pattern to transfer through to your dart, creating the dart extension. No tracing wheel? Cut along outside the edge of the pattern, straight through the dart excess. Unfold your dart. The dart extension needs to be exactly the same shape as your side seam when the dart is stitched together so it doesn’t pull at the side seam.
Toile. Now do a quick toile to check your alteration and the position of the bust dart in relation to your BP/apex. The most likely alteration now is you need to lower the dart or change the length. You can pin the paper pattern together and try it on to check the dart position first but keep in mind paper doesn’t behave the same as fabric and bust darts tend to drop a little more once they are in cloth.
Not sure how to alter the dart or need a little more help with truing?…The Lower a Bust Dart Tutorial will help with that!
Useful links
The Kitty Dress FBA Tutorial
The French Dart FBA Tutorial
More to Sew …
