How to Measure for a Sports Bra – Get the Right Support for Your Activity

A sports bra is not the same as an everyday bra. It's designed to minimize breast movement during physical activity – and that changes how it should fit.

If you've ever worn a sports bra that felt too tight in the band, too loose in the cup, or just didn't give enough support, you know the struggle. The good news? It's all about getting the right measurements and choosing the right impact level for your activity.

This guide will help you measure for a sports bra that works for your body and your workouts – whether you're running, doing yoga, or hitting the gym.

Why Sports Bras Fit Differently

Sports bras are engineered to reduce breast movement during physical activity. Unlike everyday bras, they typically have:

• A firmer, tighter band – because most support comes from the band, not the straps
• Less stretch in the fabric – to keep everything in place
• Wider straps – to distribute weight and prevent digging
• Different cup styles – compression (flattening) or encapsulation (separate cups)

Because of these differences, your sports bra size may be different from your everyday bra size. Many women need to size down in the band and up in the cup for high-impact activities.

Understanding Impact Levels

Sports bras are categorized by the level of support they provide:

Your activity level determines the type of sports bra you need – and the size you should choose.

How to Measure for a Sports Bra

Measuring for a sports bra is similar to measuring for an everyday bra, but with a few key differences:

Step 1: Measure Your Underbust (Snug)

• Wrap the tape around your ribcage, directly under your bust.
• Pull it firmer than you would for an everyday bra – sports bras need a tight band for support.
• Make sure the tape is level.
• Write down this number.

Step 2: Measure Your Bust (Standing)

• Measure around the fullest part of your chest – usually across the nipples.
• Keep the tape loose – don't compress the tissue.
• Write down this number.

Step 3: Calculate Your Band Size

• For sports bras, use your snug underbust measurement directly – do not add 4-5 inches like you would for everyday bras.
• Round to the nearest even number (e.g., 32" → 32 band).

Step 4: Calculate Your Cup Size

• Subtract your band size from your bust measurement.
• Each inch of difference equals one cup letter (1" = A, 2" = B, 3" = C, etc.).

For high impact, you may need to size up in the cup and size down in the band for maximum support.

Not sure about your numbers? Use our Bra Size Calculator to get your base size, then adjust for sports.

Sports Bra Size Adjustments by Impact Level

* These are general recommendations – always try on different sizes for the best fit.

Use our Sports Bra Calculator to get your exact size based on your measurements and activity level.

Compression vs Encapsulation – Which Is Right for You?

• Compression bras flatten the breasts against the chest. They work well for smaller busts and low-to-medium impact activities. They're simple, comfortable, and easy to wear.
• Encapsulation bras have separate cups that hold each breast individually. They provide better support for larger busts and high-impact activities. They reduce bouncing and distribute weight more evenly.

Many high-impact sports bras combine both compression and encapsulation for maximum support.

Tips for Trying On Sports Bras

• Test the band – It should be firm and not move when you move your arms. You should be able to fit two fingers under it comfortably.
• Check the cups – No spillage at the top or sides. The center piece (gore) should lie flat against your chest.
• Jump and move – Do a few jumping jacks or jog in place to test for bounce. If it feels unsupported, try a size down in the band or up in the cup.
• Check the straps – They should be comfortable and not dig in. Adjustable straps are useful for different body shapes.
• Try sister sizes – If the band feels too tight, try a sister size up (e.g., 34C → 36B). If it feels too loose, try a sister size down (e.g., 34C → 32D).

Use our Sister Size Calculator to find your options.

Frequently Asked Questions