Swimsuit Size Chart A US women’s Small (size 4-6) equals a 33-36″ bust, 27-30″ waist, and 37-40″ hip. A US Medium (size 8-10) equals a 36-39″ bust, 30-33″ waist, and 40-43″ hip. Men’s sizes run on waist alone — a Medium equals a 32-35″ waist.
This guide breaks down women’s swimsuit size charts, men’s swimsuit size charts, kids’ sizing, brand-specific variations, and exactly how to measure swimsuit size at home. You’ll also find quick answers to the most common sizing questions people search for before buying.
Women’s Swimsuit Size Chart
A woman’s swimsuit size isn’t the same as her regular dress size. Swimwear brands size around bust, waist, and hip circumference because stretch fabric needs to hug the body in ways a blouse or jeans don’t.
Size
US Numeric
Bust (in)
Waist (in)
Hip (in)
XS
0-2
30-33
24-27
34-37
S
4-6
33-36
27-30
37-40
M
8-10
36-39
30-33
40-43
L
12-14
39-42
33-36
43-46
XL
16-18
42-45
36-39
46-49
XXL
20-22
45-48
39-42
49-52
Plus Size Swimsuit Chart
Plus size swimwear starts around XXL (size 16-18) and extends to 4X or 26+. The measuring method stays identical — bust, waist, hip — but brands add extended cup sizing (D, DD, F cups) for one-piece suits and underwire bikini tops, since standard bra sizing doesn’t map cleanly onto swim fabric.
Swim trunks and board shorts size loosely, similar to casual shorts.
Jammers and swim briefs, built for training and racing, use a compression fit — they’re meant to feel snug and firm when dry, then ease slightly once wet.
Kids’ swimwear skips adult measurements entirely, using height, weight, and waist instead — since a child’s torso proportions change faster than an adult’s.
Size
Age
Height (in)
Weight (lbs)
XS
4-5
39-43
35-45
S
6-7
44-48
45-55
M
8-10
49-53
55-80
L
12-14
54-58
80-120
XL
16
59-63
120-160
How to Measure Swimsuit Size
How to Measure Your Bust or Chest
Wrap the tape around the fullest part of your chest, keeping it level across your back. Don’t hold your breath or pull the tape tight — a snug, not squeezing fit gives the truest number.
How to Measure Your Waist
Find your natural waistline — the narrowest point, usually an inch above your belly button. Breathe normally while measuring; sucking in gives a false reading that leads to a too-tight suit.
How to Measure Your Hips
Measure around the widest part of your hips and seat, keeping the tape parallel to the floor the whole way around.
How to Measure Torso Length for One-Piece Suits
This step gets skipped in most basic size charts, but it matters for one-piece swimsuits. Run the tape from one shoulder, down through the crotch, and back up to the same shoulder — this diagonal circular torso measurement determines whether a one-piece will pull, gap, or ride correctly.
Sizing isn’t universal. A Medium at Speedo won’t always match a Medium at Nike or Arena, because each brand builds its pattern around a different body model.
Brand
Type / Size
Sizing Details
Speedo
Recreational Suits
Closer to standard measurements
Speedo
Training & Racing / Fastskin / LZR
Tighter by design; dedicated sizing system
Nike
Training Swimsuits
26–42 = XS–XXL; measures torso, bust, waist, and hip
Arena
Recreational Swimwear
Separate sizing chart
Arena
Tech Suits
Typically 1–2 sizes smaller
TYR
Recreational Swimwear
Separate sizing chart
TYR
Tech Suits
Typically 1–2 sizes smaller
US vs International Swimsuit Sizes
US Size
UK Size
EU Size
AU Size
XS (0-2)
6-8
32-34
8-10
S (4-6)
10-12
36-38
12-14
M (8-10)
14
40-42
16
L (12-14)
16-18
44-46
18-20
XL (16-18)
20
48
22
FAQs
What’s the best swimsuit brand for plus size?
Torrid, Lane Bryant, Swimsuits For All, and Calypsa are among the best plus size swimsuit brands, offering sizes 14 to 36 with good support and fit.
What size swimsuit should I buy?
Measure your bust, waist, and hips, then match them to the brand’s size chart, since swimsuit sizes vary by brand and usually run 1 size smaller than regular clothes.
I am the admin and author of SizesForm, researching, verifying, and explaining measurements, dimensions, weights, and sizes in simple terms to help readers understand everyday comparisons accurately and confidently.
