Ysolda's sizing chart for knitwear designers
Years ago I shared the sizing chart I used for calculating my garment patterns. It didn't survive a website migration, and I've made adjustments over the years based on feedback from knitters. Finally, here's the updated version.
It's a google doc so you can use it as the basis of your sweater grading spreadsheets. The second sheet in the file gives explanations of where on the body each measurement is taken. They are all body measurements.
Essentially this is a compilation of sizing charts from a range of sources, including the ASTM standard charts for misses and plus-size women and several patternmaking manuals. It's specifically intended for grading hand knitting patterns rather than sewn garments and follows knitting industry conventions (at the simplest level, for sewn garments it would be normal to grade sizes so that measurements of the smaller sizes are closer together than larger). I definitely do not recommend using this for purposes other than knitting patterns.
CYCA Standards Many publications require designers to follow the sizing charts published by the Craft Yarn Council. These lack measurements and, I suspect, cause some confusion around shoulder widths and armhole depth. I've tried to make a chart that follows the sizes set up in that chart but with a wider range of measurements. When designing for other publications it's always a good idea to double check whether there's a specific sizing chart they'd like you to follow.
You'll notice that some lengths are consistent across the size range. This is because the sizing chart is based on women of the same average height across the size range. Whether larger bust sizes should also be proportionally taller is a matter of some debate, and you may wish to make slight adjustments to these measurements.
The length of the underarm to neck area *will* increase between sizes, some designers handle this by reducing the sleeve and body lengths as the sizes increase.
Personally I prefer to keep sleeve and body lengths close to the same across the size range allowing knitters to make adjustments as required for height independent of bust size. The exception is for very close fitting garments where a little extra length is required to follow the curves of the body in larger sizes.
You'll notice that the difference between some of the smaller measurements is very small, and that the rounding is more accurate than you'd usually see in a knitting pattern. This is simply to reflect the distribution across the size ranges and isn't an indication that the actual garment measurements are this accurate.
The conversion between inches and metric are not accurate. The conversion is intentionally done at 1" = 2.5cm because knitting patterns usually give gauge over 4" or 10cm. These measurements will reflect the measurements a knitter will get following the gauge directions for their chosen system. In practice we probably can't expect a level of accuracy with gauge which would make a difference here!
Learning more about grading
I'm hoping to put together a tutorial, or maybe online class, on how I approach grading patterns in excel — if you have any specific things you've been wondering about please let me know. In the meantime you might want to check out Marnie Maclean's tutorial . Or Faina Goberstein's Craftsy class. I found the class a bit difficult to follow, like most Craftsy classes it's very slow and it would have benefitted from screen sharing but you might find it a helpful introduction. Every designer has a slightly different approach to this so seeing how different people work is really valuable.