Sports Bra Size Calculator
Find the exact size you need based on activity impact level — engineered to reduce up to 83% of breast bounce.
📐 Performance Parameters
Measure just below your breasts
Fullest point across the chest
Activity Impact Level
🏃♀️ High Impact — Choose Support Style
Sports Bra Fitting & Impact Level Guide
During exercise, un-supported breasts move in a figure-eight pattern, bouncing up to 14 cm during high-impact sports like running. Because breast tissue consists of soft glandular tissue and delicate Cooper's ligaments (which lack elasticity and cannot repair once stretched), wearing the correct high-support sports bra is essential for biomechanical support and pain prevention.
Our Sports Bra Size Calculator evaluates your standard UK measurements and activity type to calculate whether a compression or encapsulation sports bra fit is best for your cup size and exercise intensity.
Yoga, Pilates, Walking
Requires gentle hold without restrictive compression. Soft-touch crop tops and seamless bralettes allow full thoracic rotation and deep diaphragmatic breathing.
Cycling, Gym, Hiking
Balances motion control with comfort. Moderate compression or hybrid encapsulation cups hold tissue in place during directional changes and strength training.
Running, HIIT, Equestrian
Demands maximum motion reduction (up to 80% bounce control). Encapsulation sports bras with wide padded shoulder straps and firm underbands are strongly recommended.
Compression vs. Encapsulation
Compression Bras work by pressing breasts flat against the chest wall. They are highly effective for A–D cup sizes during low to medium impact exercises.
Encapsulation Bras enclose each breast in an individual structured cup, supporting tissue from beneath. Recommended for DD+ cups and high-impact activities.
The 5-Point Sports Fit Check
- ✓ Underband: Sits firm and level around the ribcage. Fits no more than two fingers beneath the elastic.
- ✓ Cups: No breast tissue spillage over the neck or underarms; no fabric puckering.
- ✓ Straps: Padded and non-slip; no digging into collarbones during arm movement.
- ✓ Centre Front: Sits flat against the chest bone in wired encapsulation styles.
- ✓ Bounce Test: Jump in place — breasts should move synchronously with your torso.
Sports Bra FAQs
How should a sports bra fit compared to a normal bra?+
It should feel noticeably tighter and more secure than your daily bra, but not restrict breathing. The underband needs to sit level across your back, and you should be able to fit exactly two fingers under the elastic band.
Do I size down in a sports bra?+
If you are purchasing a compression style bra for high-impact activities, going down one cup size can help lock tissue in place. For encapsulation styles, choose a sister size with a smaller band and larger cup (e.g., from 34D to 32DD) to secure the band anchor.
What is the difference between compression and encapsulation sports bras?+
Compression bras flatten the breast tissue against the chest to restrict bounce (great for A-D cups). Encapsulation styles feature separate cups to support and isolate each breast (recommended for DD+ cups and serious bounce control).
Should I wear an underwired sports bra?+
For fuller busts, an underwired encapsulation sports bra provides the highest level of bounce reduction. For yoga, pilates, or smaller busts, wireless styles offer greater flexibility and sufficient support.