About Us
Bra Size Calculator is a free educational website that helps you estimate your bra size from two simple body measurements: your underbust and your bust. Everything on the site runs in your browser — there are no accounts, no sign-ups, and no fees.
Why This Site Exists
Bra sizing is confusing. Sizes are not standardized between brands, sizing systems differ between countries, and many people end up wearing a size that doesn't fit comfortably simply because they were never shown how to measure. We built this site to make the basics — measuring, calculating, and understanding size charts — clear and accessible to everyone, for free.
What the Calculator Does
The bra size calculator takes your underbust and bust measurements and estimates your band size and cup letter in your country's sizing (US, UK, EU, FR, AUS, JP or IN). It offers a simple mode (two measurements) and an advanced mode (six measurements for a more refined estimate). It also links you to the sister size calculator, which shows sizes with a similar cup volume on a different band.
How to Use This Site
- Measure: follow our step-by-step measuring guide to get your underbust and bust numbers.
- Calculate: enter the numbers in the calculator to get your estimated size.
- Compare: look up the size on our bra size chart, including US, UK, and EU conversions.
- Learn: browse the blog for plain-language guides on measuring, size charts, and sister sizes.
Educational Purpose and Limitations
This site is an educational tool. The calculator produces an estimate, not a guaranteed fit — bra sizing varies between brands, styles, and manufacturers, so always compare the result with the manufacturer's own size chart. Nothing on this site is medical advice. For more detail, see our disclaimer.
If you have questions or feedback about the site, you can reach us through the contact page.