Bra Size Calculator
Calculate your bra size based on band and bust measurements with sizing options.
Get instant, accurate results
What is this?
A bra size calculator helps you determine your correct bra size by using your band and bust measurements. It can convert between different sizing systems (e.g., US, UK, EU) and provide fit recommendations based on your measurements.
How to Use the Bra Size Calculator
Your training only includes information which existed until October 2023. The critical factor for your comfort and support depends on your bra size determination. The best outcome requires you to understand your body measurements which determine your appropriate bra size.
The Bra Size Calculator is a tool that will enable you to get the right bra size based on the measurements of your underbust and bust. The Bra Size Calculator uses bra size and cup size and measurement differences to determine your correct bra size.
The bra size calculator uses your personal measurements to provide specific recommendations which differ from standard size charts. The best fit for your body requires different measurement methods to match your body shape and size.
The bra size calculator provides an excellent tool for finding your most comfortable bra size which works for all situations including everyday use and sports bras and lingerie.
1. Select Measurement Unit
Select your preferred unit of measurement between inches and centimeters.
You must use identical measurement units when measuring both bust and underbust dimensions. The calculator will convert all input values from centimeters to inches for precise size calculations.
2. Measure Your Bust Size
You need to measure your bust at its most complete point while you are wearing a non-padded bra.
The user should maintain the measuring tape at a straight line while they should keep the tape tight against their body. The measurement should be entered as it was taken because this method provides the most precise results.
3. Measure Your Underbust (Band Size)
You need to measure your body under the bust at the location where the bra band rests.
The measuring tape should be firm and straight around your body. This measurement establishes your band size because you need to round it to the closest even number.
4. Calculate the Band Size
The calculator rounds your underbust measurement to the nearest even number.
The +4 method shows additional measurements which add four inches to the band size for comparison purposes. Some manufacturers use this method.
5. Determine Cup Size
Cup size is calculated by subtracting the band size from the bust measurement.
Each inch of difference corresponds to a cup letter. Different regions (US and UK) use slightly different cup naming systems beyond DD.
6. View International Size Conversions
Your result includes size conversions for multiple regions:
• US/CA
• UK
• EU (EN 13402)
• FR/BE/ES
• Australia/New Zealand
• India
Each region uses different band number systems and sometimes different cup progressions.
7. Review Your Result
The displayed size is a starting point only.
Bra sizing may vary by brand, style, and manufacturer. It is recommended to try on different sizes and consult a professional fitting specialist for the best comfort and support.
Key Formulas Used in the Calculator
Band Size Calculation
The underbust measurement determines the band size. The value is rounded to the nearest even number because bra bands are typically manufactured in even sizes (32, 34, 36, etc.). If using inches, no conversion is required.
Cup Size Determination
Cup size is determined by the difference between the bust measurement and the rounded band size. Each inch of difference increases the cup letter. Different regions use slightly different naming systems beyond DD.
UK Cup Conversion
The UK cup system differs from the US system after DD. For example: US DDD = UK E US G = UK F This calculator converts US cup differences into proper UK naming.
European (EU) Band Conversion
European sizing increases the band number by 34. Example: US 34 → EU 68 US 36 → EU 70 US 38 → EU 72 The EU system uses centimeters instead of inches.
France / Belgium / Spain Conversion
France, Belgium, and Spain use a sizing system that adds 15 to the EU band number. Example: EU 70 → FR 85 EU 75 → FR 90
Australia / New Zealand Dress Code
Australia and New Zealand often use dress codes instead of band numbers. Example: US 34 → Dress 12 US 36 → Dress 14
Underbust +4 Method (Alternative)
Some manufacturers use the +4 method by adding four inches to the underbust measurement before determining cup size. This method is less commonly used today but still appears in certain brands.
Benefits
- Provides an accurate starting bra size based on real body measurements
- Automatically converts sizes across US, UK, EU, FR/BE/ES, Australia/NZ, and India
- Calculates proper band size using standardized rounding rules
- Determines cup size based on bust-to-band difference
- Includes alternative +4 sizing method for comparison
- Reduces guesswork when shopping online or internationally
- Helps improve comfort, posture, and overall support
When & Where to Use
- Finding your bra size for the first time
- Shopping for bras online without in-store fitting
- Converting sizes between international brands
- Re-checking size after body weight changes
- Understanding differences between US and UK cup systems
- Comparing standard sizing with the +4 method
- Finding equivalent sizes when traveling abroad
Who Should Use This Calculator
The Bra Size Calculator provides an accurate method to determine bra size which users can begin with actual measurements.
The system proves helpful to people who shop online because it enables them to compare international brands while needing to understand different sizing systems which include US and UK and EU and Indian systems.
The calculator delivers scientific estimates based on bust and underbust measurements yet users need to test sister sizes or seek assistance from professional fitters to determine their actual size.
Tips to Get the Best Deal
Measure yourself while wearing a non-padded bra for more accurate results.
Keep the measuring tape level and snug, but not tight, around your body.
Round the band measurement to the nearest even number for standard sizing.
Re-measure every 6–12 months, as body size can change over time.
Different brands may fit differently, so try sister sizes if needed.
If the band rides up, try a smaller band size.
If cups gap or spill over, adjust cup size accordingly.
Frequently Asked Questions (FAQs)
Helpful Resources
- Measure yourself while wearing a well-fitting, non-padded bra for the most accurate results.
- Take measurements at the end of the day when your body is at its largest.
- Consider trying on different sizes and styles to find the most comfortable fit.
- Remember that bra sizes can vary between brands, so use the calculator as a starting point and adjust as needed.
- Regularly re-measure yourself, as your body can change over time due to factors like weight fluctuations, pregnancy, or aging.