How do I measure my bra size at home?

Use a soft measuring tape. Measure snugly around your ribcage just below your bust for the band size. Then measure around the fullest part of your bust for the bust measurement.

How is bra cup size determined?

Cup size is the difference between bust measurement and band size. Each inch of difference corresponds to a cup size: 1"=A, 2"=B, 3"=C, 4"=D, 5"=DD, etc.

What is the difference between US and UK bra sizing?

Band sizes are the same in US and UK. Cup sizes differ starting at DD: US uses DD/DDD/DDDD, while UK uses DD/E/F/FF/G/GG/H.

Should I round my band measurement up or down?

If your measurement is odd, round up to the nearest even number. For example, a 33" ribcage becomes a 34 band. Some fitters add 4" to the measurement for looser fit.

Bra Size Calculator

Find your correct bra size in US and UK sizing from your band and bust measurements. Includes how-to measuring guide.

Band Measurement ?

inches

Bust Measurement ?

inches

US Bra Size

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UK Bra Size —

Cup Size —

Extended More scenarios, charts & detailed breakdown ▾

Band Measurement (inches)

Bust Measurement (inches)

US Bra Size

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Cup Size —

Band Size —

Professional Full parameters & maximum detail ▾

Loose Underbust (inches)

Snug Underbust (inches)

Tight Underbust (inches)

Standing Bust (inches)

Leaning Bust (inches)

Lying Bust (inches)

Measurements

Recommended Band Size —

Average Bust Measurement —

Cup Difference (bust - band) —

International Sizes

US Size —

UK Size —

EU Size —

Fit Guidance

Sister Size Down —

Sister Size Up —

Shape Guide —

How to Use This Calculator

Measure snugly around your ribcage just below your bust for the Band Measurement.
Measure around the fullest part of your bust (wearing an unpadded bra) for the Bust Measurement.
The calculator shows your US and UK bra size and cup size.

Formula

Band Size = Band Measurement (rounded up to nearest even number)

Cup Difference = Bust Measurement − Band Size

1" = A, 2" = B, 3" = C, 4" = D, 5" = DD, 6" = DDD ...

Example

Band measurement 32", bust measurement 36".

Band Size = 32
Cup Difference = 36 − 32 = 4" = D cup
Bra Size = 32D (US) / 32D (UK)

Frequently Asked Questions

Use a soft measuring tape. Measure snugly around your ribcage just below your bust for the band size. Then measure around the fullest part of your bust for the bust measurement.
Cup size is the difference between bust measurement and band size. Each inch of difference corresponds to a cup size: 1"=A, 2"=B, 3"=C, 4"=D, 5"=DD, etc.
Band sizes are the same in US and UK. Cup sizes differ starting at DD: US uses DD/DDD/DDDD, while UK uses DD/E/F/FF/G/GG/H.
If your measurement is odd, round up to the nearest even number. For example, a 33" ribcage becomes a 34 band. Some fitters add 4" to the measurement for looser fit.