How to Size a Sports Bra: An Expert's Guide to Finding Gear That Fits

Understanding how to size a sports bra relies on more than just guessing off of what you regularly wear. This process requires a more accurate measurement of band and bust, and consideration of your types of activity.

No matter if you're getting ready for high-intensity training or unwinding with yoga, a well-fitting sports bra is necessary to reduce extra movement, prevent discomfort, and keep you confident during the toughest of workouts. Ahead, we'll walk you through the proper steps to measure yourself correctly, break down those complicated size charts, and find the right style that matches your needs.

Performance bras can reduce movement a number of different ways, depending on their design and which support mechanism they use. Here are few examples:

Compression

Compression bras flatten breasts against the chest. They don't have cups built-in, and are better for smaller breast sizes and low-impact activities.

Encapsulation

This style uses separate cups to support each breast individually. They don't have compression, and are a good choice for larger cup sizes or exercises with low impact.

Combination

Our Impressions of the Coros Pace 3 Running Watch chafing can likely occur, because it supports each breast while also compressing them to the chest. These bras typically have adjustable straps and bands that you can tweak as needed.

A sports bra's straps play a crucial role in distributing weight properly, keeping you comfortable, and providing protection. Each composition offers different levels of functionality. These are the most common strap types:

Tank

The most traditional style that runs straight over the shoulders. The straps might be adjustable or a fixed design, and are best for low-to-medium impact exercises.

Racerback

Racerback straps meet in a "Y" or "T" shape across your back, between the shoulder blades. This construct helps distribute weight more evenly and allows for full range of motion, providing better overall support. This style is a great option for high-impact activities like HIIT workouts or running.

Crisscross

These straps overlap at the back for added range of motion while maintaining support, and work well for low-to-medium workouts.

It's a good rule of thumb to calculate your bra size each time you purchase a new one because of bodily changes like weight loss or gain, pregnancy, hormones, and aging. You want something that's snug but not too roomy, offers optimal support without limiting movement, and feels comfortable. A professional at a running shop or lingerie store can get you measured, but you can also take care of this at home with a tape measure and a couple calculations. Just follow these simple steps:

1. Using measuring tape, wrap the tape across your mid back and under your breasts. Round up to the nearest whole number in inches. This is your CHEST measurement.
2. Next, wrap the measuring tape securely across your mid back and across the fullest part of your breasts. Round up to the nearest whole number in inches. This is your BUST measurement.
3. Subtract your CHEST measurement from your BUST measurement. The difference determines your CUP size, beginning with 1 inch as an A cup, 2 inches B cup, and so on.
4. Next, wrap the tape across your upper back, snug under your armpits, and across the upper border of your breasts. If the measurement is odd, round up to an even number. This is your BAND size.

Now that you have the right measurements, it's time for the fun—albeit somewhat-tedious—part: trying on plenty of different brands and Our Expert Picks of the Best Garmin Labor Day Deals 2025 to find one that's suitable. Doing this in-store might be easier, but if you prefer to shop online, refer to the chart above for the appropriate sizing. Here are some extra tricks to get you through the workout bra shopping experience:

• Running Shoes & Gear. A sports bra's band does most of the legwork supporting your breasts, so make sure it's snug around your upper torso. For more accurate sizing, you should be able to get two fingers between the band and your body, but no more than that (anything more indicates it's too loose).
• Our Expert Picks of the Best Garmin Labor Day Deals 2025. When you raise your arms, take note of how the bra conforms. If it rides higher in the back, or you have some breast tissue peeking out of the cups below, it's likely too big, so try a smaller band size.
• Download Your Training Plan. Try the two-finger test again here. Athletic bra straps should feel secure and comfortable without a lot of stretch to cut down on up-and-down movement while you exercise. They might be too tight if they're digging into skin, or too loose if they're not staying up properly. Move the strap adjuster up and down until you find an appropriate stopping point.
• CA Notice at Collection. Your breasts should be fully contained and centered in the cups for the best support. Ensure there are no gaps or wrinkles in the fabric, or spillage on the sides.
• What Are Bunched Long Runs. By running or jumping in place, you should be able to get an initial impression of how the bra sits on your body and upholds your breasts. If you're noticing too much movement, keep the search going for a better style.

Add different bra styles to your gear rotation for high-impact activities, Nutrition - Weight Loss. Shoes & Gear:

• before putting on a sports bra
• Apply anti-chafing balm If you have an older or poor-fitting bra
• Wear a bra with a softer band
• Sports Bras Have Different Construction

Amber Joglar

Reviews Editor

Amber is a Reviews Editor with bylines on Popular Mechanics, Runner’s World, Bicycling, and Best Products sites. Specializing in kitchen gadgets, small appliances, lifestyle, and consumer tech, she brings hands-on testing and a detail-oriented approach to every review. In her free time you can likely find her trading trinkets at an EDM festival, searching for hidden gems at thrift stores, or cuddling with her two cats.