Multi-size patterns are pretty handy when you want to customize a pattern to your own measurements. It’s normal, not everyone is one size fits all, and this flexibility allows for a more personalized fit. However, another lesser-known use for multi-size patterns is to extend the sizing range, which enables you to cater to more body shapes.
The technique below is one I think every sewist should know; not only does it give you the confidence to tackle more complex sewing projects, but it also allows you to experiment with more styles and fits because you can tailor them specifically for you. You can use this technique to size up or down!
Material needed: ruler, pencil, scissors, and silk paper or any other paper that you can see through it (optional).
Step 1: Sizing Guide
Check the sizing guide provided with the pattern, and measure the difference between the two largest or smallest sizes to find out how much the pattern is graded. The difference is often the same between the bust, waist, and hips, but sometimes it’s not. Be sure to verify that. Here for our sizing chart, we use a 4 cm (1 1/2″) difference between the sizes.
Now, you need to determine which measurement is needed for your pattern, so refer to the pattern guidelines. Some garments are loosely fitted and don’t require blending between sizes.
Then, measure the difference between the sizing guide and your body measurements and divide the result by the grading amount.
I will show you an example using our own sizing guide: if your bust measures 115 cm, subtract 109 (the bust measurement for XL) from 115 and divide the result by 4 (grading difference). In this case, the result is 1.5. This is the amount of sizes you need to extend. I use centimeters to draft my patterns, so I used metric in the example, but you can also do this with the measurements in imperial. Your measurement can also be rounded up for ease of use (3.89 to 4, 2.1 to 2, 2.35 to 2.5…). I personally recommend using whole numbers, unless there’s a lot of difference between the sizes, like 6 cm (2 3/8″) or more.
Depending on the style, you may need to repeat this step with other measurements such as waist or hips.
Step 2: Print the pattern
Print the pattern following the designer’s printing instructions. You’ll find our printing and assembling instructions here. If your pattern has layers, you may want to hide all the sizes but the two largest sizes to size up, or the two smallest sizes to size down.
Step 3: Add the grading rules
Now, take a ruler and a pencil, and trace lines connecting the two sizes at one corner. Below is the crotch/inseam corner of a pair of trousers. This line indicates which way the grading is going.
On that line, measure the distance between the two corners.
Then, multiply the measurement by the amount of sizes you need to add, and report the measurement on the line. To size up, you need to go toward the outside of the piece. To size down, go toward the inside of the piece. For this example, I went two sizes up.
Repeat this step on all the corners, notches, and markings of the pattern. You may want to work one piece at a time. To trace the new pattern pieces, connect all the reported measurements on the lines. Below is the crotch of a trouser. I traced the new pattern in green.
When you trace the new lines, it’s important to maintain the shape of the original pattern, so trace the curves carefully. Check the examples below and observe the angle at the crotch/inseam corner. The correct curve means that the angle was maintained.
Here, I graded the top of a sleeve. You can see that one side doesn’t curve enough and isn’t constant with the original pattern.
You can also use this technique to grade only one area of a pattern. For instance, if your hip measurement doesn’t fit into the sizing range and you want to make a fitted dress or leggings. Below, I corrected a dress (left) to size it down only at the hips and a pair of leggings (right) also only at the hips, but twice down.
Once you’re done, double-check that every corner, notch, and marking is reported on the new sizes.
Step 4: Trace your new pattern
If the new pattern pieces overlap, line silk paper or any other kind of see-through paper over the pattern and retrace the new pieces. Check at your local stationary or sewing supply shop!
If you can’t find see-through paper, you’ll need a tracing wheel and tracing paper to trace the new outlines. Regular paper is placed underneath the pattern, and the tracing paper is sandwiched between the two layers. When you follow the pattern outline with the tracing wheel, the pressure applied will transfer the chalk on the tracing paper to the layer of paper underneath. Note that tracing wheels can damage your work surface, so be sure to protect it with a cutting mat or cork mat.
Otherwise, just cut your directly onto the pattern following the new outlines! I think it can also be useful to note down by how many sizes you went up or down.
Of course, I always recommend making a toile if you need to size up or down by a considerable amount (4-5 sizes and up). This will ensure that the fit is suitable to your body shape!
I hope you find this tutorial helpful and that the skill you just acquired will allow you to adjust your patterns with confidence. Next time you see a pattern that isn’t available in your size, you’ll know what to do! Instead of feeling discouraged, you can now make the necessary adjustments to create something tailored to your measurements.