Bra Size Calculator

Understanding Bra Sizing and Proper Fit

Bra sizing can seem complex, but understanding the basics helps ensure proper fit and comfort. A well-fitted bra provides support, shapes your silhouette, and can significantly improve your comfort throughout the day.

Studies suggest that up to 80% of women wear the wrong bra size. This calculator helps determine your correct size using standard measurement techniques and sizing conversions between different international systems.

Basic Bra Size Formula

Cup Size Calculation

Cup Size = Bust Measurement - Band Measurement

Each inch of difference typically equals one cup size

Sister Size Formula

Sister Size = Band ± 2, Cup ∓ 1

Same cup volume with different band sizes

Measurement Guidelines

		Band Measurement: Measure around your ribcage, directly under your breasts. The tape should be snug but not tight. Round to the nearest whole inch.
	

		Bust Measurement: Measure around the fullest part of your chest, keeping the tape parallel to the floor. Don't pull tight - the tape should lie flat against your skin.
	

		Measuring Tips: Measure without a bra or with a non-padded bra. Have someone help you if possible. Take measurements at the same time of day for consistency.
	

International Sizing Systems

Different countries use different bra sizing systems:

US/Canada: Uses inches for band, letters for cups (A, B, C, D, DD, DDD, etc.)
UK: Similar to US but different progression after D (D, DD, E, F, FF, G, etc.)
European: Uses centimeters for band, letters for cups
French/Belgian/Spanish: Different numeric progression
Australian/New Zealand: Uses dress size numbers for band

Common Bra Size Conversion Chart

US/CA	UK	EU	FR/BE/ES	AU/NZ
30A	30A	65A	80A	8A
32B	32B	70B	85B	10B
34C	34C	75C	90C	12C
36D	36D	80D	95D	14D
38DD	38DD	85E	100E	16DD
40DDD	40E	90F	105F	18E

Signs of Poor Bra Fit

Here are common indicators that your bra doesn't fit properly:

Band Issues: Band rides up in back, digs into skin, or is too loose. The band should sit parallel to the floor and provide most of the support.

Cup Issues: Gaps in cups (too big), spillage over cups (too small), or the center panel doesn't lie flat against your chest.

Strap Issues: Straps dig into shoulders (band too loose), slip off shoulders (straps too long), or carry too much weight (band not supportive enough).

Wire Issues: Underwire sits on breast tissue instead of against ribcage, pokes or digs in, or doesn't follow the natural curve of your breast.

Sister Sizes and Fit Adjustments

Sister Sizes: Different band/cup combinations that hold the same cup volume. For example, 34C = 32D = 36B. Use sister sizes when you need a different band fit but want to maintain cup volume.

Shape Considerations: Bra size is just the starting point. Breast shape, width, and projection also affect fit. Different bra styles work better for different breast shapes.

Professional Fitting: Consider getting professionally fitted, especially after weight changes, pregnancy, or if you're experiencing persistent fit issues.

		Important Note: This calculator provides a starting point for bra size determination. Individual fit may vary based on brand, style, and personal preference. Always try on bras before purchasing when possible.
	