Bra Size Calculator

Enter your bust measurement and band (frame) measurement to find your perfect bra size across US, UK, EU, France, and Australia/NZ sizing systems. Choose your preferred unit (inches or centimeters), input both measurements, and get your recommended bra size with cup and band details for every major region.

Measure loosely around the fullest part of your chest, standing straight with arms at your sides.

Measure snugly (not tightly) directly underneath your breasts.

Results

Your Bra Size (US/CA)

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UK Size

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EU Size

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FR / BE / ES Size

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Australia / NZ Size

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Band Size (inches)

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Cup Size

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Results Table

Frequently Asked Questions

How do I measure my bust size correctly?

Stand straight with your arms at your sides and wear a properly fitted bra. Measure loosely around the fullest part of your chest (usually across the nipples). Record the measurement to the nearest ¼ inch or ½ cm.

How do I measure my band size?

Measure firmly (but not tightly) directly underneath your breasts, where the bra band sits. Keep the tape parallel to the ground. This is sometimes called the 'frame size' or 'underbust measurement.'

How is the cup size calculated?

Cup size is determined by the difference between your bust measurement and your band size. Each inch of difference corresponds to one cup size: 1 inch = A, 2 inches = B, 3 inches = C, 4 inches = D, and so on.

Why do bra sizes differ between countries?

Different regions use different sizing conventions. The US and UK use the same cup letters but different band numbers; European (EU) sizes use centimeters for the band; French/Belgian/Spanish sizes add 15 to the EU band number; Australian sizes follow the UK cup system with different band numbers.

What percentage of women wear the wrong bra size?

Studies and surveys suggest that anywhere from 70–85% of women wear incorrectly fitted bras. While exact figures vary by study, an ill-fitting bra can cause discomfort, poor support, and posture issues, making accurate measurement important.

Can I convert my bra size between US and UK?

US and UK bra sizes share the same cup letters (A, B, C, D, etc.) but the band sizes can differ by a few numbers. This calculator provides conversions for US/CA, UK, EU, FR/BE/ES, and Australia/NZ all at once.

What if my measurements fall between two sizes?

If your measurements land between sizes, try both the smaller and larger size. Many women find they need to size up in the band if they're between sizes, or they can try a sister size (a different band/cup combination with equivalent volume).

Should I measure in inches or centimeters?

Either works — this calculator accepts both. Inches are standard in the US and UK, while centimeters are commonly used for EU sizing. Just make sure both your bust and band measurements use the same unit.

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