All of Charm’s patterns (released after July 31, 2021) come in sizes 2-20 and 18-34, with individual pattern pieces for A-H cups. 

Many of the patterns released before July 31, 2021 have been expanded into the 18-34 size range, too, and we are working on releasing the remaining size expansion patterns as quickly as we can. Because many of our patterns are technically complex and have many cup sizes (think shelf busts, ultra-fitted dresses, and more!), the design, testing, and styling of patterns into the 18-34 block takes nearly as much time as creating a pattern from scratch. Please be patient with us as we make our way through the archive.

Which range should I choose?

The 2-20 pattern block is designed with more of an hourglass shape, and the 18-34 pattern block is designed for bodies with less waist definition.

You may notice that two sizes (18 and 20) appear in both size ranges. If you are unsure which range to use, it’s best to choose a dress size based on your High Bust measurement and cup size, then find the nearest size (in the same size range) that most closely matches your waist measurement. It’s very common to have a waist size that is different from your dress size; you will grade between sizes when cutting out the pattern pieces.

Here are measurements for both ranges so you can better assess:

Sizes 2-20

Sizes 18-34

I already purchased a Charm pattern in the old size range. Will I receive the new pattern in the 18-34 range once it’s expanded?

The 18-34 patterns use a separate pattern block and are sold as a separate product from the 2-20 patterns (meaning that you will choose either sizes 2-20 or sizes 18-34 in a drop-down menu when ordering a pattern). However, if you have already purchased a pattern in the 2-20 range and the new pattern in the 18-34 range is a better fit for you, we will be able to help you exchange your pattern files.

Please reach out to us via the Contact page of the website or through our support email. And please join our mailing list if you’d like to be updated as patterns are made available in the new size range!

When will the “X” pattern be released into the 18-34 size range? What’s the next size expansion release?

We love to keep things secret around here, but I also understand you want to know the status of all of our size expansions. Please join our mailing list if you’d like to be updated as patterns are made available in the new size range – that’s the best way to stay up to date. I promise that we are committed to working through the entire Charm archive of patterns to bring them into the 18-34 size range, and we are working on at least one size expansion project at any one time.

We’ve done most of the “easy” ones, so we’re now working on the bigger and more complex patterns, which of course take longer. The Night and Day Dress size expansion was released in early 2025, and now we’re working on something in the Lamour series.

What is the process for creating a pattern (or a pattern size expansion)?

I know a lot of you are curious about how the drafting and grading process works! I thought this might be a good chance to demystify the process a bit, and also shed some light on why expanding a pattern into a different size range can take so much time. All patterns start with a block, or a basic pattern. A block is a simple darted bodice, set-in sleeve, and basic skirt/pant. There are different blocks for knits and wovens (which, incidentally, is why it’s not usually a great idea to choose a knit when a woven is recommended).

The block is developed in a single “sample size”, which can be chosen by the designer based on the availability of a fit model, or it can be smack dab in the middle of the range. The block and the sample size conform to a size chart, which is decided individually by each sewing pattern company. This allows the company to make decisions about their ideal fit. (For Charm, we’ve always focused on a specific fit, with the waist to hip measurement ratio being larger than what you might find in a store. We also focus on bust fit, providing A-H cup sizes for every single pattern.)

Once the block is finalized, it can be used to create new patterns through flat pattern-making methods, although sometimes we use draping methods as well. Then the pattern is graded into the full range, using technical software and lots of math, and then the pattern is tested in a sampling of sizes and cup sizes throughout the range. Often, many tests and revisions are needed for each pattern to make sure the fit is correct and the design is working as intended for all sizes. We usually create more than a dozen muslins during the testing process of each pattern!

One of the most common misconceptions about sizing is that it is easy to press a button and digitally grade up a pattern to any size. If only it were that simple! Grading too many sizes from one block results in distortion and poor fit the further you get away from the sample size. We also rely on hand grading for each of the cup sizes, as this is not something that can be done digitally.

This means that our block for the 18-34 range was designed completely separately from the block for the 2-20 range, and that’s why we treat it as a separate product. When developing the 18-34 block, we had the opportunity to address any fit problems that would have started occurring had we continued grading up the size 20 even more. Based on plus size measurement charts, customer feedback, and my own discoveries from fitting students, we decided on a slightly different bust/waist/hip ratio to ensure a good fit for our 18-34 customers.

This is why there is an overlap in the two size charts (sizes 18 and 20), and why the overlap sizes are not the same measurements in each chart.

Once we’ve finished testing the pattern and we’re happy with the fit of the pattern in both size ranges, we sew some fabulous samples for the photo shoot. Finally, the pattern itself has to be created for the home sewist to use, meaning that the technical pattern files are converted and laid out into easy-to-use PDF patterns available for both home and copy shop printing. We write the instructions, create the video, and make sure our studio cat Elvira gets petted somewhere in the process, too!