I love this question because some style experts incorrectly think that plus size is a body shape all on its own. As if crossing that threshold magically changes your bone structure or where your body keeps your adipose tissue. This thinking may explain some of the downright awful plus size clothing that exists in the world - it's not designed for any actual body shape. If you encounter clothes like that in the wild, remember that there's nothing wrong with your body but there is something wrong with the minds behind those clothes. Reject those pieces like that what-was-I-thinking ex-boyfriend.
Shopping for clothes (and dating, and job hunting) isn't about measuring up to some ideal. It's about finding the right fit for you. But unlike your career or love life, you're in complete control of your wardrobe. It's up to you to reject the clothing that doesn't work for you. Don't think, "I can't wear that style." Think, "That style isn't for me."
Hybrid Body Shapes
This is where things get confusing. Your body shape may be a combination of body shapes. Some experts have identified dozens of body shapes which sounds helpful but I'm still not sure if I'm a cello or a vase, so that approach just complicates matters. Let's stick with the big 5 - hourglass, pear, apple, inverted triangle, and rectangle.
Human beings over the age of 40 are all a little bit apple - flat tummies are overrated anyway. Those of us with ample bosoms may want to take some of the advice aimed at inverted triangles, but not all if we lack the classic inverted triangle broad shoulders. So don't panic if you fit into more than one category - just pick and choose what works for your gloriously individual body.
At the end of the day, you don't need to label yourself. And you certainly don't need to create the illusion that you're one of the 10% of women who are hourglass shaped. What you need is clothing that gives you enough room to move and breathe without smothering you in excess fabric. And that means figuring out which clothing styles work with your body shape instead of fighting it.
Which One Am I?
The 5 standard body shapes are based on shoulders/bust, waist, and hips.
Hourglass - the shoulders and hips are about the same, and the waist is smaller than they are.
Rectangle - shoulders, hips, and waist are the same width/measurement.
Apples - similar shoulders, hips, and waist with larger tummies. When you look straight into a mirror, your sides are straight up and down, but when you get out the measuring tape, your waist measurement is bigger than your hips and bust.
Pear - the waist is narrower than the shoulders, and the hips are wider than the shoulders.
Inverted triangle - hips that are narrower than the shoulder and/or bust.
It may be helpful to draw on a photo of yourself - outline your figure and a shape will reveal itself. But that's not the whole story. Apple shaped women have shoulders and hips that are about the same size (like rectangles) but their tummy sets them apart. It's also helpful to get out the measuring tape, then compare your bust, waist, and hip measurements.
Here's another way to tell: Try on a sheath (straight-sided) dress or remember wearing one in the past. Does it fit comfortably all over? Than you're an hourglass, rectangle, or apple (look at your waist to figure out which). Pear shaped women will find that the hips are too tight and the top fits, or the dress fits at the hip and is too big up top. Inverted triangle shaped women will find that a sheath dress is especially roomy around their hips (though a fabric that drapes well may make it hard to tell).
When buying separates, do you get a different size for the pants/skirt than the top? Then you're an inverted triangle or a pear.
But wait, there's more.
You may be long waisted or short waisted, and that affects what styles you'll be comfortable in. You could be average height, but long waisted so petite pants fit you better. If you're tall (over 5'8") or petite (under 5'3"), you need to pay attention to where the hem of a dress, skirt, or top hits you. Certain medical conditions can give you relatively large upper arms. All that affects which styles will make you happy.
Clothes aren't usually marked with pears or apples, and so on. You need to translate your body shape into a shopping list. I've written a lot of posts with style advice for women with different body shapes. Have a look at those to figure out which styles are your new best friend. Fashion offers so much variety that even if you settle on only one silhouette, your wardrobe will never be boring.