Darling Ranges | How to do a Full Bust Adjustment (FBA)

I kind of feel like the first thing I want to say is… don’t freak out! Full bust adjustments are not scary, I promise!

Something I hear over and over from people is their trepidation about pattern alterations. Especially bust adjustments – they seem so mysterious and potentially complicated. But they’re not! Please don’t worry, it’s not beyond your ability! Honest.

WHAT THE HECK IS IT??

So, what is a full bust adjustment (FBA)?

Here’s the deal. Most patterns are drafted on a B cup. I know that’s probably upsetting those of you who aren’t B cups, but the unfortunate truth is that patterns need to draft in some sort of base standard. What does this mean for people who aren’t B cups? Well, you’ll probably need to alter your pattern to get the right fit over your bust.

DO I NEED TO DO ONE??

How do you know if you need to do an FBA on your pattern?

Easy! You know that nifty size chart you get on the back of your pattern envelope? If you find that your bust measurement falls in a larger size column than the rest of your body – then you’ll probably need to do one. If you’ve already made a muslin, you might notice you need to do an FBA because things just aren’t quite right in that area. Some symptoms may include:

• the waistline being higher at the front than the back of your bodice
• the fabric pulling around your arm syce
• an inability to close the bodice of your dress around your bust, even though you can over the rest of your body
• the dart apex hitting you too high

Ok cool. So now we know if we need one. Shall we begin the alteration?

CALCULATE THE SIZE OF YOUR FBA

Calculate how large your bust adjustment should be. This too is not scary. Just figure out what size you would be if you used your bust measurement – then compared it to what size you would be if you used your other measurements to determine your size. On the bodice front of the pattern, measure the distance between these sizes. This is how big your FBA will be!

For example, if you fall in a size 12 for your bust measurement, but fit into the size 8 category for the rest of your measurements, then you would measure the difference between the 8 & 12 front pattern pieces. Whatever the difference is, you would use that number as your FBA and use the small pattern piece to create it.

DRAW YOUR SLASH LINES

Now the fun part. Let’s draw some crazy lines all over our patterns. Kidding. They’re not crazy, they have very specific purposes.

1. First extend the dart apex along the centre fold line of the dart by 3cm (about 1 1/8 inch). We’ll call this line 1. This should be your centre bust. Mark this point.
2. Next draw a line from this point to your armsyce, about 1/3 of the way in. (this is line 2)
3. Draw a line straight across from your centre bust to the side seam. (line 3)
4. Draw a line perpendicular to grainline about 1/2 way down the dart. This line (line 4) should hit Line 1 and edge of the pattern.

Now we need to fix the waistline. The centre front is now slightly shorter. Cut along line 4, cutting completely through – then move it down till it is in line with the new waistline. I like to use my ruler to keep it straight. Tape in place.

Ok, so now your pattern piece should look similar to the photo above. As you can see, the side seam is now longer because of the wedge added with line 3. you have a couple of options here:

Option 1 – You can close the wedge back up. keeping everything else taped in place, move the bottom left piece so that line 3 is closed again. Tape down.

Doing this option means that you’re going to end up with one reeeeally large waist dart.

Redraw your dart legs. Remember your dart point is 3cm (1 1/8″) below the apex.

If you don’t want a really large dart, or your FBA amount results in a way too big dart this way, you may want to go with option 2…

Option 2 – create a second dart in the side seam using that wedge that was created. So you will have 2 darts – one waist dart and one side dart.

The dart legs of the side dart are the very edges of the cut wedge. Find the centre of both darts, and mark the dart points 3cm (1 1/8″) below the bust apex point. Redraw the dart legs.

Phew, that’s it! Now, whichever option you chose to do, now all you have to do is true your dart(s) and you’re done!

LOOKING FOR MORE DARLING RANGES POSTS?

Here’s the full list of Darling Ranges tutorials:

• Project preparation
• Pattern alterations: full bust adjustment
• Pattern alterations: small bust adjustment
• Pattern alterations: lengthen the bodice
• Pattern alterations: raise the neckline
• Pattern alterations: rounded neckline
• Pattern alterations: fishtail hem
• Pattern alterations: add darts to the back bodice pattern piece
• Sewing & construction: Bodice & darts
• Sewing & construction: Skirt & pockets
• Sewing & construction: Attaching the skirt & bodice
• Sewing & construction: Placket & Neckline
• Sewing & construction: Sleeveless version
• Sewing & construction: Attaching the sleeves
• Sewing & construction: Hemming
• Sewing & construction: Ties & beltloops
• Sewing & construction: Closures
• Sewing and Construction: Sleeveless variation
• Sewing and Construction: Dartless Versions (V2 &V3)

We absolutely love seeing what you make, so don’t forget to tag your creations with #MNdarlingranges and @megannielsenpatterns if sharing on social media.

Don’t have the pattern yet?

Order Darling Ranges today in sizes 0-20 and Curve sizes 14-30