Dressmakers Cup Sizes

How to choose the best cup size for you when making your own clothes

It’s been great to see that more and more indie pattern companies are changing their sizing to be more inclusive and offer a greater size range and also more built in alterations to patterns, such as full bust adjustments.

Often these are labelled as different cup sizes but I’ve realised that a lot of my lovely customers don’t always totally understand what the cup sizes mean as they don’t correspond to the cup size you might buy in a bra from a shop. The cup sizes labelled on sewing patterns are ‘dressmakers cup sizes’ and are a bit different.

So I wanted to give you a few examples of where you can find these cup sizes and how to work out what cup size you should use when making your own clothes from these sewing patterns.

If you would rather hear me chat about this, please check out my latest youtube video!

Why is cup size important?

If you have been finding that when you make garments they are either too tight across the bust, or the fit over the bust but drown you across the shoulder and the back, then it could mean the the cup size the pattern has been drafted for is different to your bust proportions.

You may have realised that you need to do a full or small bust adjustment, or may be doing that already on your patterns, but understanding cup sizes can save you that job and mean you get a better fitting pattern out of the packet with less tweaks and alternations to do.

What dressmakers cup size am I? How to measure your high bust and full bust

The first step in understanding and working out what dressmakers cup size you should use is to measure your high bust and your full bust.

Your high bust is the measurement that goes around your back and up and over your bust.

Your full bust measurement is the measurement of your bust at its fullest point. This is the measurement more traditionally stated on sewing patterns next to ‘bust’.

The next step is to work out the difference between the two measurements. Different pattern companies might have slightly different tolerances but generally speaking if the difference is 0-2 inches then that indicates that you are a B cup and if it is 4 inches then you are a D cup.

It’s important to know that this is a generalisation and there are variations between different companies.

Essentially, the different cup sizes in patterns will come from two separate patterns that are drafted, tested and tweaked before grading them across a size range. So for example, it’s not the case that a size 12 B-cup can be somehow graded up to a size 30 D-cup. Sizes ranges that have cup sizes will start out with a different base pattern (of the same design) and are then graded up and down to offer a range of sizes for that cup size.

What do you do if you are in between cup sizes and aren’t sure what size to choose?

This will vary depending on what the difference is between your high bust and full bust and how close it is to a cup size along with the style of the garment you are making.

So for example, if you are making a garment that is loose fitting around the bust and the difference between your high and low bust is 2.5” or even 3” then it might mean that you are ok to stick with the B-cup size range as there is enough looseness in the style of the garment anyway.

Whereas if you were making a more fitted garment that has bust darts and waist darts, it might be better to try the D-cup size. You would know for sure what would be best by making a toile or muslin but for something very fitted, its likely it will be tight across your bust if the difference between high and full bust is more than 2”.

How do I read the body size charts and garment finished measurement charts?

Within the pattern instructions, companies will typically set out two tables of sizes and what looks like LOTS of numbers.

Try not to feel overwhelmed by this and instead start by writing down your own body measurements - high bust, full bust, waist and hip for starters. Then try to hone in on them and filter out all of the other numbers and information. You might find it helpful to circle where your measurements are on the body size chart.

Once you have done that you will be able to see what size of the pattern you are falling in. It’s unlikely that this will all fit in one neat column of one size, people typically span at least one size in one of their measurements.

You can then start to get an idea of what size you might want to make. Don’t forget, what the sizes are called is arbitrary, don’t place any meaning on them, it's just a number! Some companies use a US size range but there is still variation in that, some use UK sizing, some use XS-7X. What is most important is that you base what you sew and make on your own measurements.Then next step is to look at the finished garment measurements. This will tell you, when the garment is made up in that size, what the measurements of it will be. In relation to your actual body measurements patterns will either have:

  • Positive ease - this is when the finished garment will be bigger than your actual body. For a garment made out of woven fabrics there is typically some ease, usually a minimum of about 2 inches. This is so that you can move around and get the garment on and off easily.
  • No ease - this is when the finished garment measurements are the same as your body measurement. You will see this in garments that are made from woven fabric that are designed to be very fitted. It is also common in garments that need to be made with fabric that have a little bit of stretch, so for example skinny fitted jeans that are to be made with denim that has spandex in it.
  • Negative ease - this is when the finished garment is smaller than your actual body. This is most commonly seen in garments that are made from stretchy, jersey fabric. For example a fitted t-shirt or top will often have negative ease as the fabric is supposed to stretch around the body and mean that the garment will fit.

So, if you are falling in between sizes, but the garment has a lot of positive ease, say a dress with a gathered skirt, then you may not need to make any alterations or grade between the sizes as there is already enough ease built into the style/design of the garment.

Or, if you are falling in between sizes and the garment is very fitted with little or negative ease, then you may have to grade or merge between sizes. So you may follow the lines for one size over the bust, but merge out to a different size line at the waist or hip.

What pattern companies offer different cup sizes in their range?

This is not an exhaustive list and I will try to continue to add to it over time. I’ve focused on the patterns we sell in the shop, along with some other popular PDF only patterns that are available elsewhere online. If you feel I’ve missed anything, please email [email protected] and I can amend and add to the blog post!

It’s worth noting that some patterns are only available as PDF’s in the full size range, but remember we have an A0 pattern printing service so if you see something you like that is only available as a PDF, we can print it for you!

  • Cashmerette - offer two size ranges in the patterns. Their core size range is US 12-28 Cup size C-H but they are in the process of expanding the range from 0-32.
  • By Hand London - offer sizes UK 6-24 in a B cup and UK 16-34 in a D-cup
  • Closet Core Patterns - offer sizes US 0-20 in a B cup and US 14-32 in a D-cup. They are updating their back catalogue of patterns with their US 14-32 size range.
  • Megan Neilsen - offers two size ranges, US 0-20 B cup (or 2” difference) and US 14-30 D cup (4” difference).
  • Liesl + Co - This range offers some styles in an US 0-20 size range with cup sizes A/B, C and D.
  • Chalk and Notch - offers sizes US 0-30 range with an A/B cup (with 2” difference) or a C/D cup (with a 4” difference).
  • Helens Closet - offers size range US 0-30 with sizes 0-22 in a B cup and sizes 12-30 in a D cup.
  • Tilly and the Buttons - Their range spans UK 6 - 34 with sizes 6-24 in a B cup and sizes 16 - 34 in a D cup. Their most recent pattern release, the Lyra dress, offers this size range and the Billie Sweatshirt and Jamie PJ bottoms are also now available in the 16-34 range, with more planned updates and releases on the way.
  • Grainline - offer size range US 0-18 and US14-30. Some styles are already available in the 14-30 range and they are updating their back catalogue of patterns.
  • True Bias - offer size ranges US 0-18(B-cup) and US 14-30 (D-cup).

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