Every tool on this site gives you an estimate, not a guarantee — here’s exactly what that means.
Not Medical Advice
Bra Size Calculator is a fit-education resource, not a medical or clinical service. Nothing here diagnoses, treats, or addresses a health condition. If you have pain, a lump, or any medical concern related to your chest or breasts, talk to a doctor — not a sizing calculator.
Estimates, Not Guarantees
Every calculator (Main, AI Smart Fit, Sister Size, and the rest) works from the measurements or answers you provide. If a measurement is off by an inch, the result shifts accordingly. Treat every result as a strong starting point for shopping, not a certified final answer.
Sizing Varies by Brand
The same band-and-cup number fits differently at different brands, and even between styles at the same brand. Our Brand Size Decoder gives general tendencies, not a guaranteed match — always check the retailer’s own size chart and try on when you can.
Not a Substitute for a Professional Fitting
An in-person fitting with a trained fitter — trying on multiple sizes and styles — will always be more precise than any online calculator, including this one. Use these tools as a fast, free, private starting point, not a replacement.
Questions
Email hello@bra-sizecalculator.com if anything here is unclear.