The Ultimate Bra Size Chart & Fitting Guide
Everything you need to find your perfect fit—scientifically accurate measurements, international size conversions, age-specific advice, and visual guides all in one place.
Last updated: November 15, 2023
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Why Proper Bra Fit Matters
Wearing the correct bra size isn't just about comfort—it affects your posture, breast health, and even how your clothes fit. Studies show that 80% of women wear the wrong bra size, often due to improper measuring techniques or not accounting for natural body changes.
Health Benefits
Proper support reduces back pain, improves posture, and prevents breast tissue damage from excessive movement during physical activity.
Comfort Factors
Correctly fitted bras eliminate digging straps, riding bands, and painful underwires that many women endure unnecessarily.
Aesthetic Advantages
The right bra enhances your natural shape, makes clothes fit better, and can visually take pounds off your frame.
How to Measure Your Bra Size Accurately
Step 1: Band Size
Measure snugly around your ribcage, directly under your bust. Keep the tape parallel to the floor and exhale normally.
Step 2: Bust Size
Measure around the fullest part of your bust while wearing a non-padded bra. Don't pull tight—keep the tape comfortably loose.
Step 3: Calculate
Subtract band from bust measurement to find cup size (1"=A, 2"=B, etc.). Round to nearest whole number.
Pro Tip: The Sister Size System
If your calculated size doesn't fit perfectly, try a "sister size"—one band size up with a cup size down (e.g., 34C → 36B) or vice versa. This maintains similar cup volume while adjusting band tightness. Most women can wear 2–3 sister sizes comfortably.
International Bra Size Conversion Chart
Your one-stop, idiot-proof guide. Start with your current size, or measure yourself below.
| US/UK 🇺🇸🇬🇧 | EU 🇪🇺 | France 🇫🇷 | Australia 🇦🇺 | Japan 🇯🇵 | Cup Volume |
|---|---|---|---|---|---|
| 28AA | 60AA | 75AA | 6AA | 60AA | Very Small |
| 30A | 65A | 80A | 8A | 65A | Small |
| 32B | 70B | 85B | 10B | 70B | Small-Med |
| 34C | 75C | 90C | 12C | 75C | Medium |
| 36D | 80D | 95D | 14D | 80D | Large |
| 38E | 85E | 100E | 16E | 85E | X-Large |
| 40F | 90F | 105F | 18F | 90F | XX-Large |
| 42G | 95G | 110G | 20G | 95G | Plus |
| 44H | 100H | 115H | 22H | 100H | Plus+ |
| 46J | 105J | 120J | 24J | 105J | Super Plus |
Tip: If your size isn't listed, use the measuring guide or sister size chart below.
Sister Sizes (Your Plan B for a Perfect Fit)
| Your Size | Go Down a Band (Up a Cup) | Go Up a Band (Down a Cup) |
|---|---|---|
| 34C | 32D | 36B |
| 36D | 34DD/E | 38C |
| 38DD | 36E | 40D |
If your usual size is sold out or feels off, try your "sister size" for a better fit.
Fit Tips & International Shopping Advice
- Try before you buy. Brands and styles vary in fit—even with the same size label.
- Sister sizes can save you if your band or cup isn't available.
- EU/FR sizes: Band numbers are in cm. FR adds 15 to EU band size (EU 75 = FR 90).
- Australian: Band number is smaller (e.g., UK 34 = AUS 12).
- Japanese: Uses EU band numbers, but cups may differ (some brands skip double letters).
- If in doubt: Always measure yourself. See the "How to Measure" above.
Scientific Bra Fit Principles
Band Size Science
The band provides 80% of a bra's support. It should fit snugly on the loosest hook when new (hooks tighten as elastic wears out). You should be able to fit two fingers comfortably under the band.
Cup Fit Check
Your breasts should fully fill the cups without spillage or gaping. The center gore should lie flat against your sternum. Wires should encase breast tissue without digging in.
Weight Fluctuations
A 5–10 lb weight change can affect bra size. Measure every 6 months or after significant weight changes. Pregnancy can change size dramatically—measure each trimester.
The Anatomy of a Perfectly Fitted Bra
- Have a band that stays parallel to the floor all around your body
- Show no breast tissue spillage at the sides or top
- Have straps that don't dig in but provide light support (only 20% of total support)
- Have underwires that follow your breast root without poking
- Allow you to breathe comfortably while providing support
Age-Specific Bra Fitting Guide
Teens (11–18)
Key Considerations: Rapid growth, sensitivity, modesty concerns
Recommended: Soft-cup bras, stretchy fabrics, adjustable straps
Frequency: Measure every 3–6 months during growth spurts
Special Notes: First bras should be comfortable and non-restrictive. Sports bras often preferred for active teens.
Young Adults (19–35)
Key Considerations: Style preferences, activity levels, possible pregnancy
Recommended: Variety of styles for different outfits/activities
Frequency: Measure annually or after weight changes >10 lbs
Special Notes: This is when many women establish their "base size" before pregnancy-related changes.
Adults (36–55)
Key Considerations: Hormonal changes, possible weight fluctuations
Recommended: Supportive styles with wider bands, full coverage
Frequency: Measure every 1–2 years or after major life changes
Special Notes: Perimenopause can cause breast size fluctuations. Consider professional fittings.
Seniors (56+)
Key Considerations: Comfort, ease of dressing, posture support
Recommended: Front-closure bras, wireless options, soft fabrics
Frequency: Measure every 2–3 years unless experiencing changes
Special Notes: Arthritis-friendly closures and softer materials become more important.
Bra Fit Problems & Solutions
Band Riding Up
Problem: Band moves up your back
Solution: Try a smaller band size (e.g., from 36 to 34) and adjust cup accordingly
Spillage
Problem: Breast tissue overflows cups
Solution: Go up a cup size or try a fuller coverage style
Gaping Cups
Problem: Empty space in cups
Solution: Try a smaller cup size or different cup shape (balconette vs full cup)
Shoulder Grooves
Problem: Straps dig into shoulders
Solution: Tighten band (providing more support) and loosen straps
Wire Discomfort
Problem: Wires poke or dig in
Solution: Check wire width matches breast root or try wireless styles
Back Bulge
Problem: Band creates back rolls
Solution: Try a wider band or longline bra style for better distribution
Specialty Bra Sizing
Sports Bras
Measure while wearing your regular bra. High-impact sports need compression or encapsulation styles. Band should be snugger than everyday bras.
Fit Tip: Jump in place during fitting—minimal bounce indicates proper support.
Maternity/Nursing
Measure at fullest pregnancy point. Look for stretchy cups, wider bands, and easy-open clips. Size fluctuates during breastfeeding.
Fit Tip: Buy nursing bras in third trimester when ribcage is expanded.
Plus Size
Focus on supportive wide bands, full coverage cups, and reinforced straps. Side support panels help with shaping.
Fit Tip: Look for bras with at least 3 columns of hooks for better support.
Post-Surgery
Soft, wireless styles recommended initially. Pocketed bras accommodate prosthetics. Measure after swelling subsides.
Fit Tip: Front-closure bras are easiest during recovery.
Still Unsure About Your Size?
Try our virtual fitting tool or schedule a video consultation with our bra experts
Start Virtual FittingBra Care & Replacement Guide
When to Replace
Every 6–12 months with regular wear. Signs: stretched elastic, loose hooks, faded color, uncomfortable fit.
Proper Washing
Hand wash in cool water with mild detergent. If machine washing, use a lingerie bag and delicate cycle.
Drying
Always air dry—never put bras in the dryer as heat damages elastic and shape.
Rotation
Rotate between 3–4 bras to extend lifespan. Elastic needs 24+ hours to recover between wears.
Extending Your Bra's Lifespan
- Fasten hooks before washing to prevent snagging
- Wash after 2–3 wears to prevent oil buildup that degrades elastic
- Store bras stacked or laid flat to maintain shape
- Alternate between bras to allow elastic to rest
- Replace when the band stretches out beyond the tightest hook
Final Thoughts on Finding Your Perfect Fit
Remember, bra sizing is more art than science—your perfect fit might vary between brands and styles. Use this guide as a starting point, but don't hesitate to try different sizes and styles to find what works best for your unique shape. Your bra size can change 5–6 times throughout your adult life due to weight fluctuations, hormonal changes, pregnancy, and aging, so regular measurements are key.
When in doubt, consult with a professional bra fitter—many specialty lingerie stores offer free fittings. The right bra should make you feel supported, comfortable, and confident in your own skin.
