Athletic Wear Size Guide: Activewear Sizes and How They Should Fit
Gym, running and team-sport clothing uses ordinary letter sizes, but the cut changes the answer: a compression top and a relaxed training tee in the same size fit very differently. Here are the charts, what each fit type is designed to do, and the sport-specific quirks that catch people out.
Athletic wear uses the same letter sizes as everyday clothing. A men's medium fits a 38-40 in (97-102 cm) chest and 31-33 in (79-84 cm) waist; a women's medium fits a 36.5-37.5 in (93-95 cm) bust and 38.5-39.5 in (98-100 cm) hip. Buy your normal size in fitted and relaxed cuts; for compression gear, size by the chart rather than by feel, since it is meant to be tight.
- Men's M chest
- 38-40 in (97-102 cm)
- Women's M bust
- 36.5-37.5 in
- Youth YL
- sizes 14-16
- Youth XL ≈
- adult S
On this page
Men's athletic wear size chart
Most sportswear brands publish chest, waist and hip ranges for each letter. Use chest for tops and jackets, waist for shorts and tights. The values below are typical; any one brand may sit an inch either side.
| Size | Chest | Waist | Hip |
|---|---|---|---|
| S | 34-36 in (86-91 cm) | 28-30 in (71-76 cm) | 35-37 in (89-94 cm) |
| M | 38-40 in (97-102 cm) | 31-33 in (79-84 cm) | 38-40 in (97-102 cm) |
| L | 42-44 in (107-112 cm) | 34-36 in (86-91 cm) | 41-43 in (104-109 cm) |
| XL | 46-48 in (117-122 cm) | 37-40 in (94-102 cm) | 44-47 in (112-119 cm) |
| XXL | 50-52 in (127-132 cm) | 41-44 in (104-112 cm) | 48-51 in (122-130 cm) |
If your chest and waist fall in different sizes, buy tops by chest and bottoms by waist. Athletic builds with a large chest and small waist often take an L top and M shorts. Plain cotton tees for training follow the same chart, covered in more detail in the t-shirt size guide.
Women's athletic wear size chart
| Size | US | Bust | Waist | Hip |
|---|---|---|---|---|
| XS | 0-2 | 32.5-33.5 in (83-85 cm) | 24.5-25.5 in (62-65 cm) | 34.5-35.5 in (88-90 cm) |
| S | 4-6 | 34.5-35.5 in (88-90 cm) | 26.5-27.5 in (67-70 cm) | 36.5-37.5 in (93-95 cm) |
| M | 8-10 | 36.5-37.5 in (93-95 cm) | 28.5-29.5 in (72-75 cm) | 38.5-39.5 in (98-100 cm) |
| L | 12-14 | 39-40.5 in (99-103 cm) | 31-32.5 in (79-83 cm) | 41-42.5 in (104-108 cm) |
| XL | 16-18 | 42-44 in (107-112 cm) | 34-36 in (86-91 cm) | 44-46 in (112-117 cm) |
Tops with a built-in shelf bra fit by bust first; if your bust is a D cup or larger, a separate sports bra under a loose top usually works better. Inseams, lengths and plus sizes for tights are in the leggings size chart.
Compression, fitted or relaxed: what each fit means
Activewear labels describe how much room (ease) the garment has over your body. The same size in a different fit category feels like a different size.
| Fit | Room over the body | Used for | Sizing advice |
|---|---|---|---|
| Compression | Smaller than the body; stretches on | Base layers, recovery, high-output training | Follow the chart exactly; do not size up for comfort |
| Fitted / slim | Close, 0-2 in over the body | Running, cycling, layering | True to size |
| Athletic / regular | About 3-5 in over the chest | Gym training, everyday sport | True to size |
| Relaxed / loose | 6 in or more | Lifting, basketball, warm-ups | True to size, or size down if between sizes |
Sportswear "compression" has no common pressure rating, so one brand's compression shirt can feel twice as tight as another's. Medical compression garments are rated in mmHg and sized by limb measurement; the leggings guide explains the difference.
How to measure for activewear
- Chest or bust. Around the fullest part, under the armpits and across the shoulder blades, arms relaxed. Wear a sports bra if you are measuring for women's tops.
- Waist. For shorts and tights, measure where the waistband will sit, typically at or just below the navel.
- Hip. Around the fullest part of the seat, feet together.
- Inseam. From the crotch to the ankle bone for tights, or to where you want the hem for shorts.
- Height. Many brands list a height range per size for one-piece items, cycling bibs and youth wear. Use it when your measurements sit on a boundary.
Sizing by sport
Running
Running shorts come with 3, 5 and 7 in inseams (8, 13 and 18 cm), with 5 in a common middle choice, and usually include a liner that fits like briefs. Tights should not bunch at the ankle, because loose fabric rubs over long distances. Running socks are sized by shoe size; see the sock size chart.
Cycling
Cycling shorts and bib shorts are cut to be close-fitting so the pad (chamois) stays in place. Italian and other European cycling brands are often cut a size smaller than US sportswear, and many riders go up one size from their usual letter. Bib shorts also depend on torso length: if the straps cut into your shoulders, you need the next size or a tall version.
Gym and weight training
Freedom at the shoulders, hips and knees matters more than a close fit. Squat-proof leggings or shorts with 7-9 in inseams suit leg work; a relaxed or athletic-cut top avoids restriction in overhead lifts. More on inseam lengths is in the shorts size guide.
Swimming, yoga and winter sports
Swimwear follows its own charts, with competitive suits sized smaller than recreational ones; see the swimming suit size chart. Yoga clothes need stretch more than a particular size, with a high-rise waistband that stays put in forward bends. Ski and snowboard pants are sized by waist with room for a base layer and mid layer, so most people buy their normal size; go up only if you wear a thick insulating layer underneath.
Youth athletic sizes
Youth sportswear and team uniforms use YXS to YXL. Each letter covers two numeric kids' sizes.
| Youth size | Kids' size | Typical age | Chest |
|---|---|---|---|
| YXS | 4-5 | 4-5 years | 24-26 in (61-66 cm) |
| YS | 6-8 | 6-8 years | 26-28 in (66-71 cm) |
| YM | 10-12 | 9-11 years | 28-30 in (71-76 cm) |
| YL | 14-16 | 12-14 years | 30-32 in (76-81 cm) |
| YXL | 18-20 | 14-16 years | 32-34 in (81-86 cm) |
Team jerseys are often ordered for a whole season, so choosing the next size up for a child near the top of a range is sensible. Adult S follows directly after YXL in chest size but has a longer body and sleeves.
Frequently asked questions
Should I size up or down in workout clothes?
Buy your usual size in relaxed and fitted cuts. For compression tops and tights, follow the brand chart exactly: if you size up to make it comfortable, you lose the support it is designed for. Size up in cycling kit from European brands and in cotton pieces that may shrink.
Is a youth XL the same as an adult small?
Close. Youth XL (sizes 18-20) fits about a 32-34 in (81-86 cm) chest, while an adult men's small fits about 34-36 in (86-91 cm). Youth cuts are also shorter in the body and sleeves, so a tall teenager usually needs the adult size.
What size athletic shorts for a 34 inch waist?
A 34 in (86 cm) waist is a men's large in most activewear charts, which covers about 34-36 in. If you are at the bottom of the large range and the shorts have a drawcord, a medium may also fit.
Do athletic clothes shrink?
Polyester and nylon performance fabrics barely shrink if washed cold and air-dried. Cotton and cotton-blend training tees can shrink noticeably in a hot dryer, mostly in length. High heat also damages elastane, which makes leggings and compression gear lose their grip.
How should a sports bra fit?
Firm around the band, with no bouncing during movement and no spillage at the cups. Sports bras are sized by band and cup or by letter linked to bra size; the details are in our sports bra size guide.