Find Your Perfect Bra Size in Seconds
Our bra size calculator helps you estimate your best fit using simple measurements, international size conversions, and practical fitting guidance.
Bra Size Calculator
Enter your measurements below
Find Your Bra Size in 3 Easy Steps
Our bra measurement calculator makes finding your perfect fit simple and accurate. No more guessing — just quick, reliable results.
Measure Your Underbust
Wrap a measuring tape snugly around your ribcage, just below your breasts. Keep the tape level and note the measurement in inches or centimeters.
Measure Your Bust
Wrap the tape around the fullest part of your bust. Don't pull too tight — the tape should be snug but comfortable. Stand straight and breathe normally.
Get Your Size
Enter your measurements into our calculator and instantly receive your bra size in US, UK, EU, and other international sizing systems, plus sister size recommendations.
Bra Size Calculator Tools
Comprehensive tools to help you find your perfect bra size, convert between sizing systems, and discover sister sizes.
Bra Size Calculator
Calculate your exact bra size using underbust and bust measurements. Get results in US, UK, EU, and 7+ international sizing systems instantly.
Calculate Now →Sister Size Calculator
Find your bra sister sizes — alternative sizes with the same cup volume but different band sizes. Perfect when your exact size isn't available.
Find Sister Sizes →Bra Size Conversion
Convert bra sizes between US, UK, EU, FR, IT, AU, JP, and more international sizing systems. Essential for shopping from international brands.
Convert Sizes →Cup Size Calculator
Determine your exact cup size from your bust and underbust measurements. Understand what each cup letter means and find your perfect cup fit.
Find Cup Size →Band Size Calculator
Calculate your correct bra band size from your underbust measurement. A properly fitting band provides 80% of your bra's support.
Find Band Size →Sports Bra Calculator
Find the right sports bra size for your activity level. Our calculator considers impact level and recommends the best support for your workouts.
Find Sports Size →Bra Size & Measurement Guides
Everything you need to know about bra sizing, measuring, and finding the perfect fit — written by lingerie fitting experts.
How to Measure Bra Size
A complete step-by-step guide to measuring your bra size accurately at home. Learn the proper technique used by professional fitters.
Bra Measurement Chart
Complete bra size charts for US, UK, EU, and international sizing. Find your size quickly with our easy-to-read measurement tables.
Bra Size Conversion Chart
Convert between US, UK, EU, FR, IT, AU, and JP bra sizes with our comprehensive international conversion chart and guide.
Bra Fitting Guide
Learn how to tell if your bra fits correctly. Identify common fit problems and discover simple solutions for a more comfortable fit.
Sister Sizes Explained
Understand how sister sizes work, when to use them, and how to switch sizes when your usual band or cup is unavailable.
Bra Sizing Blog
Browse practical articles about bra sizing, measuring tips, fit problems, style advice, and shopping guidance.
Frequently Asked Questions About Bra Sizing
Our bra size calculator uses standard underbust and bust measurements to estimate a strong starting size. It compares your inputs across US, UK, EU, and other international sizing systems. For the best result, measure while wearing a non-padded bra or no bra, and use advanced mode if you want a more detailed estimate.
To measure your bra size at home, you'll need a soft measuring tape. First, measure your underbust (band size) by wrapping the tape snugly around your ribcage just below your breasts. Then, measure your bust at the fullest point while standing straight. Enter both measurements into our calculator to get your size. For detailed instructions, visit our how to measure bra size guide.
Sister sizes are bra sizes that share the same cup volume but have different band sizes. For example, 34C, 32D, and 36B are all sister sizes. When your exact size isn't available, you can try a sister size. Going up a band size means going down a cup size, and vice versa. Use our sister size calculator to find your alternatives.
It's recommended to re-measure your bra size every 6 to 12 months, or whenever you experience changes in weight, pregnancy, breastfeeding, menopause, or hormonal changes. Your bra size can fluctuate throughout your life, so regular measuring ensures you're always wearing the correct size for optimal comfort and support.
Bra sizes can vary between brands because there's no universal standard. Each brand may use slightly different sizing charts, cup shapes, and construction methods. Additionally, sizing systems differ by country (US, UK, EU, etc.). This is why our calculator provides sizes in multiple systems, and we recommend using our bra size conversion tool when shopping from international brands.
While our main calculator gives you a great starting point, sports bras often use different sizing. We recommend using our dedicated sports bra size calculator which accounts for activity level and impact. Sports bras generally need a snugger fit for adequate support during exercise.
Ready to Find Your Perfect Bra Size?
Use our detailed bra size calculator with advanced mode, international sizes, and personalized fitting recommendations.
Try Our Full CalculatorFriendly Links
Helpful text links to trusted sizing resources, reference tools, and key pages across the BraSizeHelper website.