Find Your Perfect Bra Size
Our accurate bra size calculator helps you discover your true size in seconds. No more guessing, no more uncomfortable bras.
Find Your Perfect Bra Size
Enter your measurements to find your perfect fit
Underbust Measurement
Wrap the tape measure around your ribcage, directly under your bust. Keep it snug (but comfortable) and level all the way around. Exhale normally before reading.
Bust Measurement
Measure around the fullest part of your bust. Keep the tape parallel to the floor and don't compress the breast tissue. Stand naturally with arms at your sides.
Tips for Accuracy
- Wear an unpadded bra or no bra
- Use a soft measuring tape
- Measure in front of a mirror
- Take each measurement twice
More Fitting Tools
Explore our complete suite of bra fitting calculators and guides to find your perfect fit.
Sister Size Finder
Find alternative sizes with the same cup volume for a better fit across different brands.
Find Sister SizesInternational Size Converter
Convert your bra size between US, UK, EU, French, Australian and Japanese sizing systems.
Convert SizesBreast Shape Quiz
Identify your breast shape and discover which bra styles will fit you best.
Take the QuizNursing Bra Calculator
Find the right nursing or maternity bra size during pregnancy and breastfeeding.
Calculate SizeSports Bra Calculator
Find your perfect sports bra size based on activity level and support needs.
Find Your SizeSwimwear Size Calculator
Calculate your bikini and swimsuit size for the perfect beach-ready fit.
Calculate SizeWhy 80% of Women Wear the Wrong Bra Size
Studies show that the vast majority of women are wearing bras that don't fit properly. This leads to discomfort, poor posture, and a lack of confidence. The problem? Traditional measuring methods are often inaccurate, and sizes vary wildly between brands.
Our calculator uses a modern approach that accounts for these variations and provides you with accurate sizing plus sister sizes to try.
- Accurate calculations based on your actual measurements
- Sister sizes included for cross-brand shopping
- International size conversions (US, UK, EU, AU, JP)
- Personalized fit tips based on your results
Frequently Asked Questions
Everything you need to know about finding your perfect bra size.
Our calculator provides a highly accurate starting point based on your measurements. However, bra sizes can vary between brands, so we always recommend trying on multiple sizes including the sister sizes we provide. The calculator gives you a confidence percentage to help guide your shopping.
Sister sizes are bra sizes that have the same cup volume but different band sizes. For example, 34C, 32D, and 36B are all sister sizes. When you go down a band size, you go up a cup size (and vice versa) to maintain the same cup volume. This is helpful when shopping across different brands that may fit differently.
We recommend measuring your bra size every 6-12 months, or whenever you experience significant weight changes (5+ lbs), after pregnancy, during menopause, or if your current bras feel uncomfortable. Your body changes over time, and so does your bra size!
US and UK sizing systems use different cup progressions after D cup. In the US, the progression is D, DD/E, DDD/F, G, H. In the UK, it's D, DD, E, F, FF, G, GG, H. This means a US 34DDD is equivalent to a UK 34E. Our international converter tool makes this easy to figure out!
If your calculated size doesn't feel right, try the sister sizes we provide. Also consider your breast shape - different shapes fit better in different bra styles. Take our Breast Shape Quiz for personalized style recommendations. When in doubt, consult with a professional bra fitter at a lingerie store.