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.
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:
Measurement Guide
Step-by-step instructions.
International Sizes
US, UK, EU conversions.
Sister Sizes
Alternative fitting options.
Size Charts
Complete reference tables.
Instant Results
Get your size immediately.
100% Private
Your measurements stay private.
How to Bra Size Calculator in 3 Easy Steps
Find your size:
Measure Band
Ribcage just under bust.
Measure Bust
Fullest part of bust.
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
Common Use Cases for Bra Size Calculator
Perfect for:
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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