How do I measure my bra size at home?

Measure your band size snugly around your ribcage just under your bust. Then measure your bust at the fullest point while wearing a non-padded bra. The difference between bust and band measurements determines your cup size (1 inch = A, 2 inches = B, etc.).

Why do bra sizes vary between brands?

There's no universal sizing standard. European, UK, US, and Australian systems differ. Even within one system, brands interpret sizes differently. Always try on bras or check brand-specific size charts.

What is sister sizing?

Sister sizes have the same cup volume but different band sizes. If 34C is too tight, try 36B (larger band, same cup volume). If too loose, try 32D (smaller band, same cup volume). This helps find better fits.

How do I know if my bra fits correctly?

Band should be snug and parallel to floor. Cups should fully contain breast tissue with no spillage or gaps. Center gore (between cups) should lie flat against sternum. Straps shouldn't dig in or slide off.

Women's Health Fit · 2026

Bra Size Calculator

Find your perfect bra size! Measure bust/band size in inches/cm, get US, UK, EU, and AU conversions. Learn how to measure correctly and avoid sizing mistakes.

100% FreeInternational SizesMeasurement Guide

Bra Size Calculator

Enter your bust and band measurements to calculate your bra size

Bust Size *

Measure around fullest part of bust

Band Size *

Measure around ribcage under bust

Unit

Choose measurement unit

Size Examples

Click on any example to automatically fill the calculator

Example

36" / 32"

Common US size 32D

Example

94cm / 79cm

European measurements

Example

38" / 34"

Larger cup size example

Example

35" / 32"

Medium cup size 32C

Health disclaimer: this bra size calculator is an educational fit estimate, not a medical assessment or replacement for professional clinical advice. Breast discomfort, skin irritation, post-surgical changes, pregnancy, or persistent pain should be evaluated by a licensed healthcare professional and a trained fitter.

How to Measure Bra Size Correctly?

Step-by-Step Measuring Guide:

Band Measurement: Measure around your ribcage just under your bust. Keep the tape measure level and snug but not tight.
Bust Measurement: Measure around the fullest part of your bust while wearing a well-fitting bra.
Stand Straight: Keep your arms down and maintain good posture during measurement.
Breathe Normally: Don't hold your breath - measure during normal breathing.

Pro Tip: Measure in the evening when your body is at its largest size. Wear your best-fitting bra for the bust measurement.

International Size Conversion

Size System Differences:

US/UK	EU	FR	AU
30	65	80	8
32	70	85	10
34	75	90	12
36	80	95	14

Note: Cup sizes are generally consistent across countries, but band numbering systems vary significantly.

Common Bra Sizing Mistakes to Avoid

Measuring Mistakes:

Measuring over thick clothing or poorly fitting bras
Holding tape too tight or too loose
Not keeping tape measure level around body
Measuring at wrong time of day or month

Shopping Mistakes:

Assuming the same size works for all brands
Not trying sister sizes when main size is unavailable
Ignoring how the bra actually fits vs. the size label
Not getting professionally fitted when unsure

Learn More About Bra Fitting

ThirdLove Fit Guide

Expert bra fitting guide with detailed measurement instructions

Nordstrom Bra Fitting Guide

Professional fitting tips and size chart from a trusted retailer

HerRoom Sizing Guide

Comprehensive bra sizing resource with international conversion charts

Frequently Asked Questions

Measure band size under your bust, pulling tape snug. Round to nearest even number. For cup size, measure at the fullest part of your bust. Cup size = bust measurement - band measurement (each inch = one cup size).

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