A full bust adjustment must be one of the most common adjustments for people with breasts to make. Some pattern companies include multiple bodice pattern pieces with their patterns, but in most cases the front piece will be drafted for a certain cup size. In that case, you will need to adjust the front pattern piece to fit a larger bust. A look at how your RTW clothing fits you might already give you a clue. Are your button downs gaping? Your wrap tops falling open? Tight across the bust? Gaping armholes? Good in the bust but too large in the shoulders? Then you probably need one. Especially in woven garments, doing a full bust adjustment makes a huge improvement on the fit. And a better fitting garment will make you love that garment more.
When do you need a full bust adjustment
To determine if you need a full bust adjustment, you need two measurements: full bust and high bust. The difference between the high bust and the full bust measurement determines your Cup size. Compare that to the cup size of the pattern you want to make and you’ll know if you need to do an Full Bust Adjustment (FBA).
For a high bust measurement, place the measuring tape around your upper body, under the arms and above your breasts. Hold the tape snug against the skin but not tight. Viewed from the side, it will sit at an angle. For a full bust measurement, place the tape at the fullest part of your bust. Viewed from the side, it will sit parallel to the floor. This video by Threads Magazine also shows how to take these measurements.
Here’s a list of cup sizes and their difference between High Bust and Full Bust:
- A Cup: 0- 1″ (0 – 2,5 cm)
- B Cup: 1-2″ (2,5 – 5 cm)
- C Cup: 2-3″ (5 – 7,5 cm)
- D Cup: 3″-4″ (7,5 – 10 cm)
- DD/E cup: 4″-5″ (10 – 12,5 cm)
- DDD/F cup: 5-6″ (12,5 – 15 cm)
- DDDD/G cup: 6″-7″ (15 – 17,5 cm)
- H cup: 7″-8″ (17,5 – 20 cm)
All patterns used to be drafted to a B-cup, but this is changing. Especially Indie pattern companies now often offer a C as their standard, or choice between a C and a DD front piece. So if your pattern is drafted with a C-cup, and the difference between your HB and FB is 2,5″, then you don’t have to adjust the pattern. If you have a DDD/F or larger, check out Cashmerette sewing patterns, where you won’t have to do an FBA at all. The Curvy Sewing Collective has a handy list of pattern designers and the cup sizes they draft for. Paprika Patterns offers a choice between B and C cup.
How to choose a pattern size
Start by choosing your pattern size not by bust, but by high bust measurement. Some companies offer this measurement, but if not, then choose the bust measurement from the chart that corresponds with your high bust measurement. Say that your measurements are 41-32-40 (105-82-102 cm). If you would take the normal bust measurement, you’d end up with a pattern that fits in the bust, but is too big in the shoulders, armholes, sleeves and neckline. These are much harder to fit and alter in the pattern than the bust. Instead you cut out 38-32-40 (96-82-102 cm). So by going with the high bust measurement you ensure that it will already fit in those areas, and you will adjust fit in the bust.
How much to add in your adjustment
Now that you have established your need for an FBA, you need to check how much extra room you need to add to your pattern. For this you need your measurements and the size chart. First, take your high bust measurement, say 38″ (96 cm). Then, take your bust measurement, say 41″ (105 cm). The difference is 3″ (7,5 cm). Your high bust measurement places you at a size 5 in our size chart, so that is the size you cut out. Then you need to add 3″ (7,5 cm) in total to the bust area on the pattern. Considering that the pattern piece is one half of the bodice, you need to add 1.5″ (3,75 cm) to the bust area.
What does a full bust adjustment look like?
After the adjustment, the pattern piece will be unchanged in the shoulders and neckline. The armscye will be more curved but still the same length. The bust dart will be wider, and can be longer or shorter depending on where your apex is. The front below the armhole will be wider and longer. The grey areas in the illustration below show where room has been added to the patten, the red line the new outline of the pattern.
FBA for different types of bodices
The Full Bust Adjustment works different depending on the type of pattern piece. Does it have a bust dart or not, a waist dart, a raglan sleeve, or princess seams? The tutorials below will guide you in making these full bust adjustments.