Swimsuit Sizes: Complete Sizing Guide

Swimsuit sizes vary by style and gender. This guide covers women's one-piece, bikini, men's trunks, and board shorts with international size conversions and measurement charts to help you find the perfect fit.

Women's One-Piece Swimsuit Sizes

Women's one-piece swimsuits are sized by bust, waist, and hip measurements.

Size US UK EU Bust (inches) Waist (inches) Hip (inches)
XS 0-2 6-8 32-34 32-33 24-25 34-35
S 4-6 10-12 36-38 34-35 26-27 36-37
M 8-10 14-16 40-42 36-37 28-29 38-39
L 12-14 18-20 44-46 38-40 30-32 40-42
XL 16-18 22-24 48-50 42-44 34-36 44-46

Bikini and Two-Piece Sizes

Bikini tops and bottoms can be sized separately for a better fit.

Top Size Bust (inches) Cup Size Bottom Size Hip (inches)
XS 32-33 32A-32B, 34A XS 34-35
S 34-35 32C-32D, 34B-34C, 36A-36B S 36-37
M 36-37 34D, 36C-36D, 38B-38C M 38-39
L 38-40 36DD, 38D-38DD, 40C-40D L 40-42
XL 42-44 40DD+, 42D+, 44C+ XL 44-46

Men's Swim Trunks and Board Shorts

Men's swimwear is sized by waist measurement in inches or centimeters.

Size Waist (inches) Waist (cm) Inseam Trunks Inseam Board Shorts
S 28-30 71-76 5-7 inches 17-19 inches
M 32-34 81-86 5-7 inches 19-21 inches
L 36-38 91-97 5-7 inches 21-22 inches
XL 40-42 102-107 5-7 inches 22-23 inches
XXL 44-46 112-117 5-7 inches 23-24 inches

Visual Size Comparison

Swimsuit size comparison from small to large.

Swimsuit size comparison XS M XL

Swimsuit Size Calculator

Find your swimsuit size based on measurements.

How to size swimsuits correctly

Measure first, label second

Pick a tape measurement and match it to the chart. Labels (S/M/L, US/UK/EU numbers) drift between brands; the underlying body measurement does not. Bust, waist, and hip measurements over the underwear you'll wear. Swimsuits should be tight when dry; they relax in water.

Picking between two sizes

Pick the smaller of two sizes for one-piece and bikini tops; pick the larger for high-cut bottoms. Synthetic spandex blends loosen with chlorine and sun exposure over a season.

Brand and regional variation

The same labeled size can differ by a full size between brands and regions. Asian brands generally run a half size smaller than US brands; European brands fall in between. When in doubt, use the centimetre or inch measurement on the size chart, never the letter.

Common mistakes

  • Sizing by your old favourite without checking the new brand's chart.
  • Skipping the measurement step. Body shape changes; old numbers go stale.
  • Picking too tight in non-stretch fabrics — they don't break in the way leather does.
  • Trusting a single review's "runs small / runs large" without looking at the reviewer's measurements.