Enter both measurements to continue.
A schematic fit diagram, scaled to your cup size.
Size plus style, together
The band-and-cup formula is identical to everyday bras — a sports bra's size chart still starts from the same underbust and bust measurements. What changes is which construction actually controls movement at your cup size and activity level.
cup difference = round(bust, in) − band
Once we have your size, the activity level you pick adjusts the support-style recommendation, not the size itself — a 34D stays a 34D whether you're doing yoga or sprinting; only the construction that controls it well changes.
Construction types
Compression vs. encapsulation vs. combination
Presses, doesn't separate
Flattens the bust against the chest as one unit. Simple, comfortable, and usually enough for lower-impact movement or smaller cups.
Individual cup support
Supports each side separately, like a regular bra. Generally the better choice for larger cups or higher-impact activity.
Both at once
Encapsulated cups inside a compression outer layer — the most controlled option, common in high-impact styles for C+ cups.
Snug band, no bounce
Whatever the style, the band should feel secure without restricting breathing, and nothing should move outside the fabric during activity.
Questions
Sports bra FAQs
Many sports bra brands publish their own size charts, often S/M/L or a mix of band and cup. Use your calculated band and cup as a starting point either way.
Compression presses the bust against the chest as one shape; encapsulation supports each side individually, generally giving more control for larger cups during higher-impact activity.
Generally yes — high-impact, vertical movement causes more bounce than low-impact stretching, so running and court sports usually call for more structured support.
It can for lower-impact activity, but often struggles to control movement for larger cups during high-impact exercise, where encapsulation or combination styles tend to perform better.
The band should feel snug and supportive without restricting breathing, and cups should fully contain tissue without bounce — tighter than loose, never painfully restrictive.
Also useful