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

How do I measure my bra size?

Measure band snugly under your bust; round to the nearest even number. Measure bust at its fullest point. Cup size = bust − band: each inch = one cup (A = 1 in, B = 2 in, C = 3 in, D = 4 in, etc.).

What do the numbers and letters mean?

The number is the band size in inches (US); the letter is the cup size = bust − band in inches. Example: 34C means a 34-in band with 3 in of cup.

What are sister sizes?

Bras with the same cup volume but different bands. 34C ≈ 32D ≈ 36B. If your usual size doesn't fit but the cup seems right, try a sister size.

How do US, UK, and EU sizes compare?

Band: US and UK use inches; EU uses cm (band/2 + 5). Cups: US and UK diverge above D (US uses DD/DDD, UK uses DD/E/F). EU uses continuous letters without DD.

How often should I remeasure?

At least annually, and after significant weight changes, pregnancy, or if bras feel tight or loose. Most people wear the wrong size until remeasured.

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