The term grading refers to the blending of multiple sizes of the same pattern. This is more common than you might think. We humans are too varied and fantastic to fit into 20 standard shapes! Pattern grading is a fairly simple adjustment you can make to get the best fit at different parts of your body by using multiple sizes at multiple points. Let’s dive in!
1. First, take your measurements…
This may sound simple, but bodies change and you ought to be working with the most up-to-date information! Follow the sizing directions on our Pattern Sizing page to determine your circumference measurements (chest/bust, waist, abdomen, hip, etc). These are the most important. It’s also good to note the length of the garment or recommended body height. Length is easy to adjust (and we’ll talk about that later), but it’s less important for choosing sizes.
2. Find your closest sizes on the measurement chart
For this example, let’s fit our Solo Dress pattern for a teen/adult body with the following measurements (in inches):
High Chest: 36.25
Full Bust: 39
Waist: 32.5
Abdomen: 39
Hip: 41.75
Their 2.75″ chest/bust difference puts them in the C-cup, with 36 dictating the size 10 in the bust (10C). The waist and below measurements are much closer to the 12, so they will need to grade between those two sizes.
3. Redraw side seams to reflect the blend of sizes
The next step is simply to find the right size at the right point in the pattern piece. Start with the bust size (10) at the bust and upwards (shoulder, neckline, armscye, etc). At the waist and below, they are a 12, so between the bust and waist we need to redraw a new curve that goes from one line to the other.
Front bodice darts should follow the bust size. Back darts depend on the garment. For garments with an individual bodice or skirt piece, you can follow the bust or hip size for those darts. For the solo dress there is one combination dart that handles both the bodice and hip/abdomen. We find that following the abdomen measurement for back darts is usually best in our solo dress pattern.
For other pattern pieces that touch the bodice, we should use the size that the bodice is at that point. Since the armscye and neckline are size 10, we would use size 10 for the sleeves and collar. Since the bodice is size 12 at the bottom edge, we would use size 12 for all skirt and skirt frame pieces.
4. What if there are princess seams?
Princess seam bodices replace the darts with vertical seams emanating from the armhole or shoulder. The same method can be used here. Using the measurements in our previous example, the wearer would simple re-draw the sides of the pattern piece between the bustline and waistline.
Let’s take length into account too
High Chest: 32 (size 4)
Full Bust: 33.75 (size 4)
Waist: 27.75 (size 6)
Abdomen: 35.5 (size 8)
Hip: 38.5 (size 8)
Desired length of garment: 27 (1.5 inches shorter than pattern)
In this example, the wearer spans 3 pattern sizes, and must also adjust the length of the pattern.
The length of the pattern can be adjusted as indicated on the pattern piece (this is above the waistline in many patterns but can vary). The bodice can be sliced along the adjustment line and either spread apart to add length, or overlapped to shorten. For our Solo Dress pattern, we recommend making 2/3 of the adjustment where indicated in the bodice, and 1/3 by shortening the skirt at the hem. In this case, the bodice can be sliced and overlapped 1 inch, leaving 1/2 inch of shortening to happen at the skirt hem edge.
Once this is done, the sizes can be blended using the same method to re-draw the side seams. Remember to use the size 8 skirt pieces (since it attaches at the abdomen) and size 4 sleeves (since they attach above the bust).
A more drastic example (for bodices with darts)
High Chest: 32 (size 4)
Full Bust: 33.75 (size 4)
Waist: 29.25 (size 8)
Abdomen: 34.5 (size 6)
Hip: 37.5 (size 6)
Desired length of garment: 27 (1.5 inches shorter than pattern)
Adjustment using previous method is shown in blue.
When the bust and waist are 2+ sizes different, making adjustments only at the side seams might end up with an awkward shape, actually curving out at the waist as shown in the upper image. This likely is not representative of the actual person’s figure! When adjusting a pattern like we did in the above examples, we have not altered the waist darts at all, only the side seams. This means that in the front, the garment is still coming in at the waist the same amount as before, and we’re adding all our extra at the sides. Realistically the persons’ body is probably going in at the waist a little less on all sides. Reducing the size of the darts can help us balance and redistribute the extra circumference we’re adding.
Choose an amount to move the side seam in. I often start with 1/4 – 1/2 inch. Bring the dart in by that same amount at the waistline (half on each side). I’m going to use 1/2 inch in this example, so I’ll adjust the dart by 1/4 inch each side. Then bring the side seam in by the total amount (1/2 inch). The width across the bodice front waist is unchanged, but the distribution of the waist decrease is more even. Depending on the wearer’s shape, you can do this in the front, back, or both. When there are 2 darts, such as in the back shown, move half the amount to each dart (1/2 inch total = 1/4 inch each dart = 1/8 inch each side of each dart).
This also works the opposite way. When the waist is significantly smaller, make the darts bigger. Though in most cases the person may just fit into the next size up of bust cup (when applicable, such as in our solo dress pattern).
Note: This dart adjustment is not necessary when using princess seams – we are already doing this when we re-draw the side-front and side-back princess seams!
When grading works, and when it doesn’t!
Blending sizes in this manner works best for the middle of the body, from chest to hips. For broad or narrow shoulders, it’s generally more effective to do a regular shoulder adjustment, rather than trying to grade to a different size in the shoulder (especially for garments with sleeves).
While blending sizes should give you a closer fit overall, it’s always a good idea to make a mock-up/muslin to check and make small adjustments.
Keep in mind the type of garment you’re working with. Our solo dress examples are quite fitted all the way down. For a garment that’s loose through the waist (such as our Howe top/dress), it may not matter if the wearer’s waist measurement is a size off of everything else.
If you’re new to making fit adjustments to your patterns, start small and practice to gain your skills! Grading between sizes like this is a great place to start.
If you’re interested in learning more, check out our digital download, Pattern Alterations for Better Fit.
Happy sewing!