Bra Size Guide & Conversion Chart 2026: Find Your Perfect Fit ( US, UK, EU, AU & Japan )
Finding the perfect bra size is notoriously difficult—especially when shopping online. Did you know that a \”C cup\” in the US is completely different from a \”C cup\” in Japan? Or that your band size might change depending on whether you are shopping from a UK or European brand?
Finding your perfect fit shouldn\’t be a guessing game. Our international bra size converter is designed to help you navigate different regional standards effortlessly, ensuring you get the support you deserve.
This comprehensive guide is designed to cut through the confusion. Whether you are shopping for American DTC brands or navigating cross-border sizes from Japan and Australia, we’ll help you find your true fit, reduce the need for returns, and shop with confidence.
Why Is Bra Sizing So Confusing?
Bra sizing is not universal. It’s a mix of different measurement units (inches vs. centimeters), varying cup measurement methods, and confusing labeling systems.
- Inches vs. Centimeters: US/UK use inches; EU/Japan use centimeters.
- Double Letters: The UK uses FF, GG, etc., while the US often stops at DDD.
- Shape & Grading: Japanese bras often fit \”smaller\” due to different padding and grading shapes compared to Western brands.
Understanding these differences is key to getting the support you need.
How to Measure Your Bra Size at Home
Follow these three steps to find your starting size.
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Step 1: Measure Your Underbust (Band)
The band provides 80% of the support. It wraps around your ribcage, directly underneath your bust tissue.
- Wrap the measuring tape snugly around your ribcage, directly under your bust.
- Make sure the tape is parallel to the floor.
- Exhale naturally and record the number (e.g., 34 inches or 75 cm).
- Fit Tip: A correct band should feel firm. If it rides up your back, it is too large.
Step 2: Measure Your Bust (Cup)
The cup size is simply the difference between your ribcage measurement and your bust measurement.
- Wrap the tape around the fullest part of your bust (usually strictly across the nipples).
- Wear a non-padded bra or go braless for accuracy.
- Stand naturally without holding your breath.
Step 3: Calculate Your Size
Subtract your Band size from your Bust size.
- US/UK Rule: Generally, each letter represents a 1-inch increase in bust volume (1\” = A, 2\” = B, 3\” = C…).
- Example: Underbust 34\” + Bust 37\” = 3 inch difference. Result: 34C.
International Bra Size Conversion Chart (Core Reference)
Use the bra size conversion chart below to see how your measurements translate across US, UK, EU, and AU standards. This is essential for understanding how a specific size, like a 36/80 bra size in cup, might be labeled differently depending on the brand\’s origin.
| US / Canada | UK | Europe (EU) | Australia (AU) | Japan (JP) |
| 32A | 32A | 70A | 10A | 70A |
| 32B | 32B | 70B | 10B | 70B |
| 32C | 32C | 70C | 10C | 70C |
| 34C | 34C | 75C | 12C | 75C |
| 36D | 36D | 80D | 14D | 80D |
| 36DD / 36E | 36DD | 80E | 14DD | 80E |
| 38DDD / 38F | 38E | 85F | 16E | 85F |
| 38G | 38F | 85G | 16F | 85G |
| 40H | 40FF | 90H | 18G | 90H |
Pro Tip for Japan Sizing: Japanese cups often run smaller and feature more padding than Western brands. Many customers find they need to size up one cup letter (e.g., if you are a US 34C, try a Japanese 75D).
Regional Systems Explained
United States (US) & Canada
- Units: Inches
- Common Confusion: The letter after D varies significantly. Some brands use DD, DDD, G; others use E, F, G.
United Kingdom (UK)
- Units: Inches
- The Gold Standard: Known for the most consistent progression for fuller busts (DD, E, F, FF, G, GG).
- Note: A UK \”E\” cup is often larger than a US \”DD\”.
Europe (EU)
- Units: Centimeters
- Simplicity: No double letters. A, B, C, D, E, F… purely alphabetical.
Japan (JP)
- Units: Centimeters
- The \”Asian Fit\”: Bands tend to run snug, and cups are designed for an uplifted, centered silhouette. Sizing advice: consider sizing up in the cup if you prefer a less compressed fit.
Sister Sizes: The Secret to a Perfect Fit
Can\’t find your exact size? Or does the band feel too tight but the cup is fine? Try a Sister Size. These are sizes with the same cup volume but different band lengths.
The Golden Rule:
- Band Size DOWN ↓ = Cup Letter UP ↑
- Band Size UP ↑ = Cup Letter DOWN ↓
Example: If you wear a 34C, your sister sizes are 32D (tighter band) and 36B (looser band).
Sister sizing is essential for flexible fits like Wireless Bras and Bralettes. [Shop Wireless & Bralette Collection]
Troubleshooting Common Fit Problems
- Spillage (Quad-boob): The cup is too small. Try one cup size up.
- Gapping at the top: The cup is too large or the style doesn\’t match your breast shape. Try a Demi Cup or Balconette.
- Band riding up: The band is too big. Size down the band and size up the cup (Sister Sizing).
- Straps digging in: The band isn\’t doing its job. Tighten the band hooks or size down the band.
Frequently Asked Questions
A: Generally, no. Japanese cups tend to run smaller than US cups due to padding and shape differences. A US C cup is often closer to a Japanese D cup.
A: To convert the band size: 32 inches is approx 70cm, 34 is 75cm, and 36 is 80cm. For cups, a 1-inch difference is roughly equal to 2.54cm.
A: The most common mistake is wearing a band that is too loose and a cup that is too small. If your straps are constantly falling down or the back band rides up between your shoulder blades, you likely need a smaller band size.
A: The \’36\’ refers to the US/UK band size in inches, while \’80\’ refers to the European/International band size in centimeters. Both represent the same physical size. To find your 36/80 bra size in cup (A, B, C, etc.), you simply measure your full bust and subtract your underbust as shown in our guide.
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