Do you have a store-bought pattern, but need it in a different size? Changing a pattern from one size to another is called grading. Here’s a quick lesson on how to do that.
The pattern you have probably has the sizes stacked, or nested together. If it’s a vintage pattern that only came in one size this tutorial won’t help you, you’ll need to learn grading and grade rules, which is much more complicated that what I’m about to show!
You can see some areas have a large change between sizes, and some areas have little to no change. These are grade rules, and they differ at critical points of the garment. They have to match from one piece to another, so if the underarm is extending this much, the sleeve also has to extend that much in that spot.
For this tutorial I’ll show how to grade up, but you could easily apply these techniques and grade down instead 🙂
I’m measuring the difference from one size to the next. All of the sizes increase 1/4” at the side seam except the size 12, which increases 3/8”. This is pretty common for larger sizes to have larger than average differences between each size. So I’m going to follow the same grade rules, adding 3/8” at the side seam.
I’m following the angle of the pattern piece to connect the line. At the curve I mark the notch at the same 1/4” grade as the previous size.
I’m using a curved ruler to draw the curve, trying to match the shape of the smaller sizes.
Same thing at the shoulder, measure the distance and add it again. Draw the straight lines following the previous patterns, and the notches too.
This armscye mark is a little harder because of the change in grade rules. So I’m following the line of the smaller sizes, but aligning my ruler with the larger size, and marking the same distance out.
It might look confusing at first, but it’s all pretty repetitive, and you’ll get the hang of it quickly 🙂
Did you know clothing manufacturers have “tolerance” when they’re sewing? Fabric gets cut in stacks, so there might be 12 layers of fabric that’s being cut at once! Sometimes it stretches or shifts in cutting. And machine operators must sew quickly to meet deadlines and might not be as accurate as you or me sewing at home. So the garments have a tolerance at critical points, like the waist, hem, and length. For example, the waist might have a tolerance of 1/4″, so let’s say the target measurement is 32″, then the finished garment can measure anywhere from 31.75″ to 32.25″. This means the waist measurement of pants you buy at the store might have a half-inch of difference, even of the same size!
