5 Butt Shapes Explained (And Which Underwear Actually Suits Each)

Butt shapes are mostly genetic — fat distribution, muscle structure, and hip-to-glute ratio are decided long before any squat program. Knowing yours doesn't mean accepting it; it just means you stop spending money on underwear that was cut for someone else's anatomy.

Five common shapes, how to identify yours, and which underwear, jeans, and lingerie actually work.

The mirror test (60 seconds)

Stand in front of a full-length mirror in fitted underwear. Look at yourself in profile and from the back. Three reference points:

1. The hip line — at your hip bones, are you wider, narrower, or about the same as your butt?
2. The crease — the line where your butt meets your thigh. Is it sharp, soft, or barely visible?
3. The shape from the back — does the butt look round, flat, square, or pointed at the bottom?

Match the description that fits.

1. Heart (A-Shaped)

The shape: Round and full at the bottom, narrower toward the top where it meets the lower back. The fullest point is below the crease line. Often goes with a defined waist and pear-shaped bodies.

You have this if: Your butt looks like an upside-down V from the back, with the volume concentrated low.

Best underwear: Cheeky and brazilian cuts. They sit at the right point on the curve and flatter the round bottom without bunching. High-leg cuts elongate the leg line.

Best jeans: High-rise with a slight stretch. They cup the bottom rather than crushing it down. Bootcut and flared jeans balance the proportions.

Best lingerie: Bodysuits with high-cut leg openings. Cheeky-back bralettes and matching sets.

Skip: Boyshorts (cut across the fullest point — bunching), low-rise jeans (cut into the upper curve in a flattening way).

2. Inverted Heart (V-Shaped)

The shape: Fuller at the top near the lower back, narrower at the bottom. Often comes with broad shoulders and an athletic upper body. The crease line may be sharp.

You have this if: Your butt looks fuller toward the top and tapers down to thinner thighs.

Best underwear: Boyshorts and full-coverage briefs work well — they add visual fullness across the bottom half. Cheeky cuts emphasize the top-heavy shape rather than balancing it.

Best jeans: Mid-rise with back pocket detail (decorative stitching, larger pockets) — adds visual fullness to the lower curve.

Best lingerie: Bottom-detail panties (lace, ruffles, contrast trim at the leg openings).

Skip: High-leg cuts (extends the V-shape further), seamless thongs (give you nothing to balance against).

3. Square (H-Shaped)

The shape: Hips and butt are approximately the same width. Hip line continues down through the butt without curving in. Common with rectangle and athletic body types.

You have this if: From the back, your butt looks more like a rectangle than a circle.

Best underwear: Cheeky cuts with contrast at the leg openings — adds dimension. Brazilian cuts that sit slightly below the natural waist create curve. Padded panties (yes, they exist) are made for this shape if you want more visual definition.

Best jeans: Curvy-fit cuts with a contoured waistband. Look for "high-rise contour" or "curve-shaping" labels — they're cut to add silhouette where the body is straight.

Best lingerie: Detail-rich pieces. Lace, embroidery, contrast trim. Bodysuits that sculpt the waist visually.

Skip: Plain cotton briefs with no detail (emphasize the straight line), low-rise styles (do nothing to add curve).

4. Round (O-Shaped)

The shape: Equally full all the way around — top, middle, and bottom. The fullest point sits in the middle of the curve, not above or below. Often the result of a strong glute development plus genetics.

You have this if: Your butt looks circular from the back, with no narrowing at the top or bottom.

Best underwear: Almost everything works. Thongs and cheeky cuts especially flatter — they let the natural shape show. Seamless options prevent visible panty lines under fitted clothing. High-leg cuts elongate.

Best jeans: Skinny, bootcut, mom jeans — round butts hold the shape of jeans well. Stretch denim is your friend (rigid denim creates pressure lines on the curve).

Best lingerie: Anything. Round butts are the marketing default for lingerie photography because they fit a wide range of cuts.

Skip: Excessively low-rise jeans without stretch (pressure lines), boyshorts that cut across the widest point.

5. Flat (I-Shaped)

The shape: Less projection, less visible curve. The butt sits closer in line with the lower back rather than projecting outward. Often goes with a slim, linear body.

You have this if: From the side profile, you don't see a strong curve — your back, butt, and thighs run roughly in line.

Best underwear: Padded briefs and cheeky cuts (yes, padding is a thing — and it works without looking obvious under clothes). Ruffled or detailed panties add visual volume. Boyshorts with seam shaping create the suggestion of curve.

Best jeans: Mid-rise with back pocket detail and stretch. Skinny jeans that taper at the ankle make the upper body and butt look proportionally fuller. Avoid seamless minimalist designs.

Best lingerie: Bodysuits with rear shaping panels. Lingerie sets with bottom-focused detail.

Skip: Plain seamless thongs (vanish without any visual lift), baggy boyfriend jeans (eliminate any silhouette you do have).

What if I'm between shapes?

Most people are. Real bodies aren't textbook diagrams. The shape categories help you understand what underwear is cut for — once you know which of two adjacent shapes is closer to yours, you'll know which cuts to try first when shopping.

The squat question

Glute training does change butt shape — but not as dramatically as fitness influencers imply. Genetic shape is set; muscle development adds size to whichever area gets trained. A flat butt with hard work becomes a muscular flat butt; a round butt with hard work becomes a more muscular round butt. The basic shape category doesn't usually shift between the five.

Underwear tip that applies to all shapes

The single biggest underwear-fit factor isn't your butt shape — it's whether the underwear is your actual size. Most people size up out of habit, then complain about wedgies and bunching. Try the size below your usual on a well-fitting cut; many will be surprised how much better it sits.

A note on the photos in your head

Most lingerie marketing photos are taken on round-shape models because round shapes hold cuts photogenically. If your butt isn't round and the underwear doesn't sit on you the way it does in the ad, that's not a flaw in your body. It's a flaw in casting.

Pick what flatters your shape. The ad version was always going to look different on you anyway.