Though the differences in body contour when interpreted through metric measurements are infinitely variable, plus size body types can generally be categorized into five general groups:
The petite designation applies to women who are on the lower end of the 5' ladder (generally between 5'0" and 5'3"), the rectangular designation is for a body shape that is mostly free of curves, the pear-shaped designation is for more bottom-heavy bodies with a narrower neck and shoulder with, the apple-shaped designation is more uniformly round body types with a broader neck and shoulder area, and the hourglass shape describes bodies with relatively proportional curves.
Depending on your unique body type, certain cuts of plus size jackets are going to be more flattering than others.
Petite body types are best off with understated jacket cuts that doesn't overtake the figure, rectangular body types fare well with jackets that simulate curves with slightly convex frames, apple shaped body types do well with looser fits, pear-shaped body types are popularly complemented by jackets that emphasize their top half with pronounced shoulders, and the hourglass body types goes well with waistline-flattering jacket cuts.
While the above guidelines are fairly well-tested trends, don't feel the need to fixate too much on obeying concrete rules for your jacket cut. Ultimately, you'll be able to determine your ideal fit through the feeling. A leather jacket is a garment that isn't just meant to cut a striking image, but also feel completely natural and empowering on you. The more relaxed and at-home you feel in your leather jacket, the more organically you'll be able to exemplify its contour.
If you want to have the best chance at acquiring a plus size leather jacket that is exactly what you need in terms of style and fit, then you're going to want to look for the vendors that have a clearly demonstrable understanding of how important the differences between uniquely proportioned plus size body types are.
Ideally, you should be able to try the leather jacket on before you make a purchase. There is no better way assess the compatibility of your body and a leather jacket than getting a direct feel for it. If you're searching online, simply make sure to closely examine how thoroughly the vendor has considered the distinction between plus sized and large size.