
Many new designers have questions about size charts, and the fear of getting them wrong often keeps many established designers in the comfort zone of accessories. This post is all about finding a starting point, moving past analysis paralysis, and how to make the best of the information available.
This post was inspired by the co-pilots on my design course, so I’m more than happy to answer further questions if you have them. That’s what the comment section is for!
Why are good size charts difficult to find?
There are three main reasons for this:
- Size charts are often seen as a brand asset. Garment fit is often used as a marketing tool or to aid positioning and competition. Think about how people are loyal to certain designers because the clothes fit well;
- Data protection – many companies conduct their own research within their customers or community. This means – unless consent was obtained at the point of access – people’s personal data (body measurements) cannot be shared;
- Many clothing and pattern retailers or individuals are private companies or individuals. They are under no obligation to anyone to share sensitive data.
This means that you have two options:
- Use something in the public domain. Examples include ASTM size charts, Alvanon’s sizing resources, or charts from the Craft Yarn Council and Knitting and Crochet Guild;
- Create your own from scratch, carrying out your own research;
- A mix of 1) and 2), adapting the data for your private use;
- Ask Kim McBrien Evans of Indigo Dragonfly for advice on sizing, or check out her resources!
I’ll go through each option below.

Creating your own size charts
Use a size chart in the public domain
This solution gets the job done, and you can rely on quality data. However, you have no in-depth information about where the data came from, nor how closely it matches the profile of your knitters. This degree of personal detachment is at odds with the immediacy and community of individual designers or smaller brands, but it is a good place to start. The availability of these charts depends on whether your country has a significant manufacturing economy. If there’s a thriving clothes making industry, and this is at least partly regulated by central government, it’s likely that there will be some publicly available resources. If not, you will have to do some digging.
Building size charts from scratch
This is what I did. My size charts are based on professional experience of fitting people and getting to know a particular body shape well. The data is not as rigorous because I’m an individual, not a large company able to commission research, but I trust myself and my knowledge and experience. I’ve spent a lot of time fitting bodies with larger-than-average busts, so my sizing skews towards a C cup at the lower end of the range, going up to an F cup. Other trends I noticed were gains in the waistline measurement with overall size, but the shoulder width remaining fairly steady with little difference between sizes. This also means that I can design for a very specific group of knitters with a particular body shape. You can have a look at my garment patterns and their schematics in my shop here.
A combination of 1 and 2
This is a good compromise if a generic chart is a bit of a curate’s egg. That is: parts of it are excellent, but a few changes are needed to some measurements. You can then tell your knitters, “My sizing is based on X, but with the following alterations: [say what they are]”, which is transparent and inspires confidence in you as a designer. It also gives them a point of reference; many people appreciate it when they can easily compare one designer’s fit to anothers. Garments are a huge investment of time, money and effort. You can also make comparisons with RTW companies if you know that your knitters definitely shop at certain stores.
Knit-focused research from Kim McBrien Evans
Kim has dedicated lots of her time to research especially for knit and crochet designers, and she has written extensively for Digits and Threads about sizing and fit. Many of her patterns come with cup size options, and she’s also happy to consult with designers to help them on their inclusive sizing journey. You can find her size chart resources here and follow her on Instagram. Kim is one of my favourite people, and volunteered a couple of tweaks to my own size chart. That’s how much she cares!

To sum it up about size charts…
For all I’ve said here, don’t be hard on yourself or feel pressured. Size charts are living, breathing, working documents – much like the humans they represent. The most important thing is to make a start and revise or tweak things as you learn, grow, and design. The design process itself can teach you a lot about sizing, and you’ll find yourself looking at your work with fresh eyes with each project.
In the same vein, don’t fall into the trap of thinking that your size chart will be set in stone one day. It’ll evolve not only with you, but with the people you dress. The image above is from my first design for Knitting magazine – and you can see that I didn’t start out knowing how to grade 12 sizes! I went back to my older work and revised it when I knew better and learnt more. It’s now the Falling Leaves sweater. Size charts have changed over time to reflect changes in fashion and lifestyle, such as corset wearing and our modern life sitting at desks. Regardless of how you get your size chart data, don’t forget that it’s part of a powerful relationship between you and other human beings.
That’s it for now – and please comment below if you have any other questions or feedback. I’d also appreciate it if you shared or saved this post so that the people who need this information can find it. Thank you for reading!
I am not a designer though I have altered knitting projects to fit me, usually by improvisational trial and error. I read your blog because it gives me an understanding and appreciation of the work that goes into good design. Thank you for an excellent read.
Thank you, Karen! Always glad to hear that my words are worthwhile ☺️