Activewear Size Charts: How to Measure Yourself Correctly

Quick answer: you need four numbers — chest/bust, waist, hips, and inseam — taken with a soft tape measure directly against skin or thin clothing, not over a hoodie. Match each number to the size chart's range rather than your usual off-the-rack size, since activewear runs closer to the body than casual clothes and brands vary by an inch or more.

The Four Measurements Every Size Chart Asks For

Chest/bust: wrap the tape around the fullest part of your chest, keeping it level front to back. Waist: measure at your natural waist, roughly an inch above your belly button, where your torso creases when you bend sideways. Hips: measure around the widest part of your glutes and hips, feet together. Inseam: measure from your crotch seam straight down to your ankle bone on a pair of pants that fit you well, or have someone measure you standing with a book pulled snug into your crotch as a guide.

Tools and Setup: Getting an Accurate Read

Use a fabric tape measure, not a metal one — it needs to curve around your body. Measure over minimal clothing like underwear or a thin base layer, standing naturally with your weight even on both feet. Don't suck in your stomach or puff your chest; the tape should sit snug enough to stay in place but not compress your skin. Take each measurement twice and use the average if the two readings differ by more than half an inch.

Reading a Size Chart Correctly

Most activewear charts list a range for each size, like a waist of 27–28.5 inches for a size Small. Find the row where all your measurements land, and if your numbers split across two rows, size up rather than down — compression fabric is easier to break in than to stretch out. For tops like the Women's Performance Crop T-Shirt, prioritize your bust and shoulder measurement. For bottoms like the Women's High Rise Topstitching Leggings, prioritize waist and hip together, since a legging can fit the waist and pull tight at the hip if your ratio differs from the chart's assumed proportions.

Men's vs Women's Measurement Points

Fixing a Bad Measurement Before You Buy

If your waist and hip numbers point to two different sizes, go with the larger size for bottoms like the High-Waisted Yoga Leggings and rely on the high-rise waistband to close the gap. For a fitted piece like the Women's Cropped Sports Bra, made from 89% polyester and 11% spandex at 230 g/m², the band should sit snug on the loosest hook so you have room to tighten it as the elastic breaks in over the first few washes.

When Charts Don't Match How a Garment Actually Fits

Fabric weight changes how a size chart translates to real fit. A thin, high-stretch knit at 130 g/m² will feel more forgiving than a structured 250 g/m² knit at the same listed size, because the thinner fabric has more give. If you're between sizes on a structured piece, size up; on a high-stretch piece, your charted size usually works as listed. Browse women's activewear or men's activewear to compare fabric weights listed on each product page before you commit to a size.

FAQ

How do I measure my waist for leggings without a tape measure?

Use a piece of string or ribbon, wrap it around your natural waist, mark where it overlaps, then lay it flat against a ruler. This gets you within a quarter inch of a real tape measure and works fine for reading a size chart.

Should I measure over clothes or against skin?

Measure against skin or a thin base layer, never over a hoodie, jacket, or jeans, since bulky fabric adds a false inch or two to every reading. Bra and waist measurements are especially sensitive to this.

What if my measurements fall exactly between two sizes on the chart?

Size up for structured or compression-heavy fabrics and stick with your charted size for high-stretch knits above 20% spandex or elastane content. When in doubt, check the specific fabric stretch percentage listed on the product page.

How often should I re-measure myself?

Re-measure every six months or after any noticeable change in training volume, since muscle and body composition shift measurements even when your weight stays the same. Waist and hip numbers tend to move first.

Once your numbers are dialed in, read our guides on what to do when you're between sizes, what actually holds during high-impact running, and fixing sports bra straps that dig in.