MathIsimple
Bra Size Calculator

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

Measure around fullest part of bust

Measure around ribcage under bust

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

How to Measure Bra Size Correctly?

Step-by-Step Measuring Guide:

  1. Band Measurement: Measure around your ribcage just under your bust. Keep the tape measure level and snug but not tight.
  2. Bust Measurement: Measure around the fullest part of your bust while wearing a well-fitting bra.
  3. Stand Straight: Keep your arms down and maintain good posture during measurement.
  4. 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/UKEUFRAU
3065808
32708510
34759012
36809514

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

Explore more health tools

BSA/BMI CalculatorWeight Loss