Bra Size Calculator
Calculate your correct bra size from band and bust measurements. Includes US, UK, EU, and AU size conversions. Find your correct bra band and cup size using standard measurement methods. Proper fit improves comfort, posture, and breast health.
Enter Values
Fill in the fields and press Calculate to see instant results.
What is the Bra Size Calculator?
The Bra Size Calculator is a free online tool that calculates your correct bra size from your band and bust measurements. It provides your size in multiple sizing systems: US, UK, EU, and AU, making it easy to find the right fit whether you're shopping locally or internationally.
Most women wear the wrong bra size. This calculator helps you find your true size using the standard measurement method. Proper fit improves comfort, support, and appearance while reducing back pain and shoulder strain.
When to Use This Calculator
- Finding Your Size: Determine your correct bra size if you've never been professionally fitted.
- Refitting After Changes: Get refitted after weight changes, pregnancy, or hormonal changes.
- International Shopping: Convert your size to UK, EU, or AU systems for international purchases.
- Comfort Issues: If your current bra is uncomfortable, recalculate to find the right size.
- Online Shopping: Determine your size before ordering bras online.
- Gift Giving: Calculate the correct size for someone else (with their measurements).
Formula & Calculation Method
The calculator uses the standard bra sizing formula based on band and bust measurements:
Cup Size = Bust Circumference - Band Circumference
Band Size = Band Circumference (rounded to nearest even number)
Cup Size Chart
| Difference (inches) | US Cup | UK Cup |
|---|---|---|
| 0 | AA | AA |
| 1 | A | A |
| 2 | B | B |
| 3 | C | C |
| 4 | D | D |
| 5 | DD/E | DD/E |
Key Variables Explained
Band Measurement
Measured snugly under the bust. This determines your band size (32, 34, 36, etc.). Measure horizontally without compressing skin.
Bust Measurement
Measured at the fullest point of your bust, loosely. This is used to calculate cup size. Measure horizontally without compressing.
Cup Size
Calculated as the difference between bust and band measurements. Each inch of difference equals one cup size.
Band Size
Your band measurement rounded to the nearest even number (32, 34, 36, 38, 40, etc.). Determines the circumference of the bra.
Note: Bra sizing varies by brand and style. Always try on bras to confirm fit, as sizing is not standardized across manufacturers.
How the Calculator Works
The calculator performs multiple calculations to determine your bra size in different systems:
Step-by-Step Calculation Process
- Collect Measurements: Band circumference (under bust) and bust circumference (fullest point).
- Calculate Cup Size: Subtract band from bust measurement. Each inch = one cup size.
- Round Band Size: Round band measurement to nearest even number (32, 34, 36, etc.).
- Determine US Size: Combine band size and cup size (e.g., 34B).
- Convert to Other Systems: Apply conversion rules for UK, EU, and AU sizes.
- Provide Sizing Chart: Show equivalent sizes in all systems.
International Size Conversions
| US | UK | EU | AU |
|---|---|---|---|
| 32B | 32A | 65A | 8A |
| 34B | 34A | 70A | 10A |
| 36C | 36B | 75B | 12B |
Worked Examples
Example 1: Average Woman
| Measurement | Value |
|---|---|
| Band | 34 inches |
| Bust | 36 inches |
Results:
- Cup Size: 2 inches difference = B cup
- US Size: 34B
- UK Size: 34A
- EU Size: 75A
- AU Size: 10A
Example 2: Larger Bust
| Measurement | Value |
|---|---|
| Band | 36 inches |
| Bust | 41 inches |
Results:
- Cup Size: 5 inches difference = DD/E cup
- US Size: 36DD
- UK Size: 36D
- EU Size: 80D
- AU Size: 14D
Example 3: Between Sizes
If your band measures 33.5 inches, round to 34. If your bust is 37.5 inches with a 34 band, that's 3.5 inches difference. Round to 4 inches = D cup. Size: 34D.
Example 4: International Shopping
US 34B = UK 34A = EU 75A = AU 10A. When shopping internationally, use these conversions to find your equivalent size.
Example 5: After Weight Change
After gaining 15 lbs: Band increases from 34 to 36 inches, bust from 36 to 38 inches. New size: 36B (was 34B). Both band and cup size increased.
Real-World Applications
Finding Proper Fit
Determine your correct size for improved comfort, support, and appearance.
Online Shopping
Know your size before ordering bras online to reduce returns and fit issues.
International Purchases
Convert your size to UK, EU, or AU systems for international shopping.
Post-Pregnancy Refitting
Recalculate your size after pregnancy and weight changes.
Health & Comfort
Proper fit reduces back pain, shoulder strain, and skin irritation.
Gift Giving
Calculate the correct size for someone else using their measurements.
Tips for Accurate Measurement
- Wear Unpadded Bra: Wear an unpadded bra or no bra for accurate measurements.
- Measure Snugly: Band measurement should be snug but not compressing. Bust should be loose.
- Stand Straight: Stand upright with good posture when measuring.
- Measure Horizontally: Keep the measuring tape parallel to the ground.
- Measure Twice: Take measurements twice to ensure consistency.
- Try On: Always try on bras to confirm fit, as sizing varies by brand.
Common Mistakes
❌ Measuring Over Padded Bra
Consequence: Padded bras add bulk, making measurements inaccurate and resulting in wrong size.
✓ Solution: Wear an unpadded bra or no bra when measuring for accuracy.
❌ Measuring Band Too Tight
Consequence: Compressing the band measurement results in a size that's too small and uncomfortable.
✓ Solution: Keep the tape measure snug but not compressing. It should slide easily.
❌ Measuring Bust Too Tight
Consequence: Compressing the bust measurement results in a cup size that's too small.
✓ Solution: Keep the tape measure loose around the bust. It should not compress tissue.
❌ Ignoring Brand Variation
Consequence: Bra sizing varies significantly by brand. A 34B in one brand may not fit the same in another.
✓ Solution: Always try on bras to confirm fit. Don't assume all 34B bras fit the same.
Quality Check: Bra sizing is not standardized across brands. Use this calculator as a starting point, but always try on bras to confirm fit.
Related Calculators
Explore these related health and fitness calculators:
Frequently Asked Questions
▶How do I measure for a bra?
▶What's the difference between US, UK, and EU sizes?
▶Why is my bra uncomfortable?
▶How often should I get refitted?
▶What if I'm between sizes?
▶Does bra size change with weight?
▶What is the difference between cup sizes?
▶Can I convert my size between systems?
Conclusion
The Bra Size Calculator is an essential tool for finding your correct bra size. Most women wear the wrong size, leading to discomfort, poor support, and appearance issues. By using this calculator and trying on bras to confirm fit, you can find a size that's comfortable and supportive.
Remember that bra sizing varies significantly by brand and style. Use this calculator as a starting point, but always try on bras to confirm fit. Get refitted annually or whenever your weight or body changes significantly.
Start using the calculator above to determine your correct bra size in US, UK, EU, and AU systems. With the right fit, you'll enjoy improved comfort, support, and confidence.
People Also Calculate
Calculators visitors commonly use alongside this one.