If you’re thinking of making an article of clothing, you’ll need to take a few measurements to determine what size of pattern and how much fabric you’ll need. Don’t get freaked out by your size in commercial patterns. Pattern sizes do not correspond to the sizes of clothing you’d buy in a store (ready-to-wear) — they are based on the circumference of your chest, waist and hips. Measure these points at the largest part and make sure the measuring tape lies flat and parallel to the ground.
The back of clothing patterns will usually have a chart showing measurements and their corresponding sizes — this is how you will know what size pattern to follow. If your measurements fall between two sizes, use your judgement for which size to use. If you go for the larger size you can take it in – but you can’t add fabric. Fit the garment to the largest part of your body — for example, you would fit a skirt to your hips, while a blouse would be based on your bust measurement. Patterns will usually show a finished measurement, which will give you an idea of how the pattern should fit.
So choose your size and start thinking about what you want your finished garment to look like.