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Free Bra Size Calculator - Find Your Perfect Fit

Calculate your bra size from band and bust measurements. Convert between US, UK, EU, and international sizing systems for accurate fitting.

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Quick Answer

To find bra size: subtract band measurement from bust measurement. Each inch equals one cup size (1"=A, 2"=B, 3"=C, 4"=D).

Key Facts about Bra Size Calculator:

  • Band size = ribcage measurement rounded
  • Cup size = bust minus band difference
  • 1" difference = A cup, 2" = B, 3" = C
  • 80% of women wear wrong size
  • Sister sizes have same cup volume

Why Use Our Bra Size Calculator?

Complete size calculations:

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Measurement Guide

Step-by-step instructions.

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International Sizes

US, UK, EU conversions.

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Sister Sizes

Alternative fitting options.

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Size Charts

Complete reference tables.

Instant Results

Get your size immediately.

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100% Private

Your measurements stay private.

How to Bra Size Calculator in 3 Easy Steps

Find your size:

1

Measure Band

Ribcage just under bust.

2

Measure Bust

Fullest part of bust.

3

Get Size

See your size in all systems.

Find Your Perfect Fit

Accurate size from measurements

International size conversions

Sister size alternatives

Improved comfort and support

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Perfect Fit
Comfort guaranteed

Common Use Cases for Bra Size Calculator

Perfect for:

First Fitting

Find your correct size.

Calculate Size

Online Shopping

Convert between sizing systems.

Convert Sizes

Size Changes

Update after weight changes.

Recalculate

Frequently Asked Questions

Everything you need to know about our bra size calculator

How do I measure for bra size?

Measure band (under bust) and bust (fullest part). Difference = cup size

Measure your band (ribcage just under breasts) and bust (fullest part). The difference determines cup size: 1"=A, 2"=B, 3"=C, 4"=D, 5"=DD/E.

What is a sister size?

Same cup volume, different band: 34C = 32D = 36B

Sister sizes have the same cup volume but different band sizes. 34C = 32D = 36B. Going down a band, go up a cup. Going up a band, go down a cup.

How do US and UK sizes differ?

Same through D cup; UK and US differ in larger cups

US and UK sizes match through D cup. After D, UK uses DD, E, F, FF, G while US uses DD/E, DDD/F, G. UK sizing is more consistent internationally.

Still have questions? Try the tool yourself!

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