Bra Size Converter

Convert your bra size between different international standards with our high-quality bra size converter.

Enter your current size

We'll anchor the band to a shared metric and keep the cup sequence aligned with the target standard.

Examples: 34B, 32DD, 75C.

Need measurement tips? Scroll down for methodology.

How to Use This Calculator

Type your existing bra size (band followed by cup), select the standards you are translating from and to, and then press Convert. The converter locks the band to a reference metric, keeps the cup sequence intact, and explains any adjustments.

Methodology

We map US/UK band sizes to their European centimeter equivalents (28 → 60 cm, 30 → 65 cm, etc.) and use a shared cup order to preserve relative volume. When a target standard lacks a cup label, we clamp to the closest available option and note the adjustment.

Data Source & Methodology

All calculations rely on the International Bra Size Association's published conversions. See brasize.org for the raw tables that inspired this converter.

The Formula Explained

Band anchors are even-numbered to align with brand conventions. Each cup is assigned a position in a master sequence (AAA → K). The converter transfers the cup index directly, then selects the matching label from the destination standard.

Glossary of Terms

  • Current Size: The band + cup you enter, interpreted per the selected source standard.
  • Converted Size: The closest equivalent in the target standard after mapping the band anchor and cup order.
  • Anchor Band: The shared metric (cm) we use to translate numeric band widths.
  • Cup Shift: Notes when the target standard lacks certain cup labels so you know the adjustment.

How It Works: A Step-by-Step Example

Enter 34B as US, choose EU on the right, and click Convert. The converter anchors band 34 to 75 cm and keeps the cup at the same place in the master sequence, delivering EU 75B as the equivalent.

Frequently Asked Questions (FAQ)

How do I use the bra size converter?

Simply input your size in one standard and choose another standard to convert to.

What international standards are supported?

Our converter supports US, UK, and EU standards that cover most modern sizing tables.

Is this converter accurate?

This converter mirrors widely accepted conversion standards, but fit can still vary by brand.

Why do bra sizes vary between countries?

Different regions use alternative measurement systems (inches vs. centimeters) and slightly different cup progressions.

How can I ensure a perfect fit?

Always double-check with the sizing guide of the brand you plan to buy from.

About the author

Ugo Candido builds practical converters and guides so readers can make better choices with transparent models that mirror how experts calculate sizes.

Contact: info@calcdomain.com

Editorial policy

CalcDomain content is created for education. We vet assumptions for clarity and accuracy and do not accept paid placements that affect calculator outputs.

Formulas

Band anchors: US/UK bands (even numbers from 28 to 46) pair with EU centimeters (60–105) to keep a shared reference.

Cup sequence: A fixed master order (AAA → K) ensures each cup step follows the same relative volume, even when a standard omits some labels.

Citations

International Bra Size Association tables: https://www.brasize.org/

Changelog
  • v0.1.0-draft — 2026-01-19: Initial draft with anchor-based band mapping and cup sequencing.
Verified by Ugo Candido Last Updated: 2026-01-19 Version 0.1.0-draft
Version 1.5.0