Bra Size Calculator
Find your correct bra size from band and bust measurements. Different brands and regions size differently — this gives the most common US standard.
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This calculator is under development.
How to use the Bra Size Calculator
- Enter your inputs into the Bra Size Calculator above.
- Results update instantly as you type — no submit button needed.
- Adjust any value to see how the result changes in real time.
The bra size calculation
Band size: round band measurement to nearest even number (US) · · · Cup size: bust − band, mapped to letter (1" = A, 2" = B, 3" = C, ...)
Measure band snugly around the underbust; measure bust at the fullest point. Subtract band from bust to get the cup gap; each inch of gap = one cup size up.
Worked example
Band 32", bust 36": gap 4 inches → D cup. US size: 32D. UK equivalent: 32DD. European equivalent: 70D. (Sizing conventions vary by country.)
Frequently asked questions
Why does bra sizing vary by country?
Cup sizing conventions differ: US uses A, B, C, D, DD, DDD; UK uses A, B, C, D, DD, E, F; EU uses similar letters but with different numerical band sizes (cm-based).
How often should I measure?
After any significant weight change, pregnancy or every 1–2 years. Most women change band size at least once in adulthood; cup size often changes more frequently.
Why is my fit different at different brands?
Brands vary in cut, materials and "vanity sizing." A 36C in one brand may fit like a 34D in another. Always try on or check brand-specific guides.