Quick answer
Choose a bodysuit by matching your bust and waist measurements to the size chart first, then check torso length and stretch level second. If you are between sizes, size up for comfort in low-stretch fabrics and stay true to size in high-stretch knits. A flattering bodysuit is one that stays put without compressing your ribs or pulling at the shoulder.
A bodysuit should feel like a second skin, not a wrestling match. The difference between a piece you reach for weekly and one that stays in the drawer usually comes down to three things: your bust and waist measurements, your torso length, and how much stretch the fabric actually has.
This guide walks through how to choose a bodysuit for your body shape using real numbers instead of guesswork. You will see how to read a size chart, where petite and tall fits change the math, and which trade-offs are worth accepting.
Start with your bust and waist numbers, not your usual size
Bodysuits are less forgiving than a loose top because the fabric connects at the crotch. That means your bust and waist measurements matter more than the size you wear in a t-shirt. Measure your bust at the fullest point and your natural waist at the narrowest point, then compare both against the chart. If your bust lands in one size and your waist in another, choose the size that fits your bust when the fabric has light stretch, and the size that fits your waist when the fabric is firm.
For example, the What Do You Say three-piece set lists a size S bust of 33.9-35.4 inches and waist of 26-27.6 inches. If your bust is 35 inches and your waist is 28 inches, you are between S and M. In a PU leather piece with slight stretch, the M gives you breathing room at the waist without gaping at the neckline.
What Do You Say
- Measure over the underwear you plan to wear with the bodysuit.
- If your bust and waist point to different sizes, let the firmer fabric area decide.
Match torso length to the cut, especially if you are petite or tall
Torso length is the most common reason a bodysuit rides up or pulls down. Petite frames often find that a standard bodysuit bunches at the waist, while tall frames feel a constant downward tug at the shoulders. Look for adjustable closures or a stretch percentage that gives you one to two inches of vertical forgiveness.
The Perfect Day One Piece Swimsuit shows how length changes across sizes: size S has a 27.6-inch length, M is 28.3 inches, and L is 29.1 inches. That roughly 0.7-inch step per size is typical. If you are tall and normally need extra length, sizing up gives you more vertical room, but check that the bust does not become too loose.
Perfect Day One Piece Swimsuit
- Petite: prioritize a higher-cut leg and a shorter torso seam.
- Tall: look for adjustable straps or a size up when length is listed.
Let stretch level decide your size-up strategy
Fabric content tells you how much the bodysuit will move with you. A piece like What Do You Say is 97% polyester and 3% elastane with slight stretch and light support, so it holds its shape but will not stretch far. In that case, size up if you are between sizes. A seamless ribbed knit behaves differently because the ribbing itself expands.
The Seamless Ribbed Sport Set lists an underbust range of 20.5-36.2 inches for XS up to 26.8-42.5 inches for XL, which shows how much a knit can flex. Use that range as your guide: if your underbust sits near the top of a size, the next size up will feel less restrictive during movement.
- Low-stretch or structured fabrics: size up between sizes.
- High-stretch ribbed knits: stay with your measured size.
Choose the neckline and back for your shape, not the trend
The neckline changes how your shoulders and bust read. A high neck or chain-link detail draws the eye up and works well if you want to balance wider hips. A scoop or square neck opens the chest and flatters a fuller bust without adding volume. Backless or tie-back styles need a secure fit at the bust, so check the size chart carefully before choosing one.
The Let's Stay Awhile set separates top and bottom sizing, which is useful if your bust and hip measurements fall into different sizes. Its top lists a size S bust of 34.6 inches and a length of 7.1/4.7 inches, while the bottoms list a size S waist range of 70-94. That split sizing lets you fit your upper and lower body independently instead of compromising.
- Fuller bust: choose a scoop or square neck with light support.
- Wider hips: a high neck or detail at the collarbone balances the line.
Decision rules for choosing your bodysuit
- If you are between sizes in a structured fabric: Size up. Low-stretch materials like the 97% polyester, 3% elastane blend in What Do You Say will not expand enough to prevent waist digging. Checkpoint: the bodysuit should lie flat at the waist without pressing into your ribs.
- If your torso is longer than average: Use the length column. The Perfect Day One Piece Swimsuit adds about 0.7 inches per size, so one size up often solves shoulder pull. Checkpoint: you can raise your arms without the crotch pulling down.
- If your bust and hips fall into different sizes: Choose a set with separate top and bottom sizing, like Let's Stay Awhile, instead of forcing one size to do both jobs. Checkpoint: the top supports your bust and the bottoms sit flat on your hips.
Catalog facts that affect fit
- Perfect Day One Piece Swimsuit: Size S length is 27.6 inches, M is 28.3 inches, and L is 29.1 inches; bust is 34.6, 36.2, and 37.8 inches respectively. The 0.7-inch length step per size tells you how much vertical room you gain by sizing up, which matters most for tall torsos.
- What Do You Say: 97% polyester and 3% elastane with slight stretch and light support; size S bust is 33.9-35.4 inches and waist is 26-27.6 inches. Low stretch means the size chart is your real limit. If you are between sizes, the next size up prevents waist pinch.
- Seamless Ribbed Sport Set: Underbust range runs from 20.5-36.2 inches in XS to 26.8-42.5 inches in XL, with pant inseams from 4.9 to 5.7 inches. The wide underbust range shows the knit flexes, so you can stay with your measured size instead of sizing up.
- Let's Stay Awhile: Top and bottoms are sized separately; size S top bust is 34.6 inches and size S bottoms waist range is 70-94. Split sizing helps if your bust and hip measurements fall into different sizes, so you fit both areas properly.
Who this approach fits best
Best for
- Shoppers who know their bust and waist measurements and want a repeatable way to pick a size
- Petite or tall frames that need to account for torso length before choosing a style
- Anyone comparing structured versus stretchy bodysuits and unsure which size to order
Not for
- Shoppers looking for a loose, oversized fit—bodysuits are designed to sit close to the body
- Anyone unwilling to measure bust and waist, since guessing is the main cause of returns
A flattering bodysuit comes down to measurements, not luck. Measure your bust and waist, check the length column if you are petite or tall, and let the fabric stretch level tell you whether to size up. Do that, and you will choose a bodysuit that stays comfortable from morning to night.
