Free Online Bra Size Calculator

Use our free Bra Size Calculator to estimate your correct bra size using your bust and underbust (band) measurements. The calculator automatically determines your cup size and converts your results into US/Canada, UK, European (EN 13402), France/Belgium/Spain, and Australia/New Zealand sizing systems. Whether you're shopping online, checking your current bra fit, or comparing international sizes, this tool provides fast, accurate, and easy-to-understand results along with a built-in Bra Size Converter for quick size comparisons.

Measure Bra Size

Input your loose bust measurement and firm underbust band measurement to calculate your baseline sizes across different regional standards.

Bust Size Band Size
Measure Bust loosely at fullest part. Measure Band firmly directly under breasts.

Bra Size Converter

Convert known bra sizes instantly to check their exact structural equivalents inside alternative international scale frameworks.

Calculated Profile

Ready to Calculate

Detailed Sizing Parameters:

How to Use the Bra Size Calculator

Our Bra Size Calculator helps you estimate your correct bra size using two simple measurements: your bust size (measured around the fullest part of your breasts) and your underbust or band size (measured firmly just below the breasts). The calculator automatically determines your recommended band and cup size and displays equivalent sizes for US/Canada, UK, Europe (EN 13402), France/Belgium/Spain, and Australia/New Zealand.

To get the most accurate result, measure your bust while keeping the measuring tape comfortably loose around the fullest part of your chest. Then measure your underbust firmly with the tape positioned directly below your breasts. Enter both measurements in either centimeters or inches, and the calculator will instantly estimate your bra size and provide international size conversions for easier shopping across different brands and countries.

Understanding Bra Cup Sizes

A bra size consists of two parts: the band size and the cup size. The band size is determined from your underbust measurement, while the cup size is estimated by comparing your bust measurement with your band measurement. Our Bra Size Calculator automatically performs these calculations and displays equivalent sizes across multiple international sizing systems.

Because different countries and manufacturers use different sizing standards, the same bra may be labeled differently while providing a similar fit. This calculator converts your measurements into the most common international sizing systems, including US/Canada, UK, Europe (EN 13402), France/Belgium/Spain, and Australia/New Zealand, making it easier to shop for bras worldwide.

Note: Bra sizing standards may vary slightly between manufacturers. The calculated size should be used as a reliable starting point, but trying on different brands and styles is recommended to achieve the most comfortable fit.

International Bra Band Size Conversion Chart

Bra band sizes are not the same across all countries. Although the fit remains similar, the size label can vary depending on the regional sizing system used by the manufacturer. For example, a US/UK 34 band is generally equivalent to an EU 75, FR/BE/ES 90, and AU/NZ 12. The table below provides a quick reference for comparing standard bra band sizes across the world's most commonly used sizing systems.

Frame Scale FR / BE / ES (cm) EU Standard EN 13402 (cm) US / UK (Inches) AU / NZ
XXS7560286
XS8065308
S85703210
M90753412
L95803614
XL100853816
XXL105904018
3XL110954220
4XL1151004422

Note: This chart is intended as a general conversion guide. While most international brands follow these standards, some manufacturers may use slightly different sizing systems. If you are shopping from a new brand, compare your measurements with the brand's size guide for the best fit.

Frequently Asked Questions (FAQs)

Measure your bust size around the fullest part of your breasts while keeping the measuring tape comfortably loose. Then measure your underbust (band size) firmly just below your breasts. Enter both measurements into the calculator to estimate your bra size.

Yes. This calculator supports both centimeters (cm) and inches (in). Simply choose your preferred measurement unit before calculating.

The calculator provides a reliable starting point based on your measurements and standard sizing systems. However, the final fit may vary slightly depending on the brand, bra style, and material.

Different countries use different sizing standards. A US size, for example, may have an equivalent EU, UK, or Australian size with a different label but a similar fit.

Bust size is measured around the fullest part of the breasts, while band size is measured directly underneath the breasts where the bra band sits.

Yes. Use the built-in Bra Size Converter to compare equivalent sizes across US/Canada, UK, Europe (EN 13402), France/Belgium/Spain, and Australia/New Zealand sizing systems.

Manufacturers may use slightly different sizing methods, materials, and cup shapes. As a result, two bras with the same labeled size may fit differently.

It is a good idea to remeasure every 6 to 12 months or whenever you experience significant weight changes, pregnancy, breastfeeding, or other body changes.

Use the calculated size as a starting point. If the bra feels too tight, too loose, or the cups do not fit properly, try a nearby size or consult the brand's fitting guide.

Yes. Our Bra Size Calculator and Bra Size Converter are completely free to use and can be accessed as many times as you need.

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