To grade means to transfer between one size line to another (or multiple) within the same garment.
Patterns are designed as an excellent starting point for a garment. Everyone’s body is different so it is very possible you should make adjustments to the pattern to make it perfect for your size and shape.
One change you might encounter, is if you fall within multiple sizes of a pattern. Your high bust (includes neck and shoulders) might be a few sizes different to your hip size.
What not to do: Don’t just choose the largest size to make your whole garment in. This will mean it will be too big for you in certain areas. One of the reasons you sew is probably to make sure something fits you well, and grading is such a simple step, so don’t be worried to include it if you need to!
Start off by looking at the Body Measurement chart. (This is very different to the Finished Measurement chart which shouldn’t be used at this point).
Compare your personal body measurements to where they fit into the Body Measurement table. Write down which size(s) your high bust, full bust, waist and hips fall under. Or for trousers you’ll compare against a different set of info.
Before we continue, if your High Bust and Full Bust measurements don’t share a size line, then instead of grading you should do a SBA or FBA to get the best fit for the Full Bust area. You might get away with grading this area if it is a very loose top but generally it’s worth just doing the adjustment to get yourself the better fit.
Step Three: (Optional fine tuning)
Now that you know what sizes each part of your body is suited to, you can use the Finished Measurement table to decide if you’re going to size up/down based on desired ease and final fit preference. If you’re unsure then ignore the Finished Measurements table and just stick with the sizes you worked out.
Step Four: (with an example below)
Example: Grading to a larger size from the bust to the hips.
Start by tracing the neckline, shoulders, and bust following the size line that matches your high bust measurement.
Once you are either underneath the bust dart, or if there isn’t a dart, then 4.5″ down from the underarm, start curving gently out towards the new size as you approach the hips. Avoid making sharp turns or curves, everything should be smooth and gradual. If you have a special curve ruler that would be perfect to help get a good transition line.
For notches, make sure you place the notches based on the size you chose for that area of the garment. For the above example you would choose shoulder, neckline, underarm and bust darts from the high bust size, and any markers, such as waist darts or hem markings from the hip size.