Bra Size Calculator
Find your perfect bra size with accurate measurements across US, UK, and European sizing systems
Calculate Your Bra Size
Measure around the fullest part of your bust while braless
Measure snugly around your ribcage, just under your bust
Fit Analysis & Recommendations
Enter your measurements above to see personalized fit analysis and recommendations.
Example Calculation
US Sizing Example
Underbust measurement: 32 inches
Bust measurement: 36 inches
Band calculation: 32 (even) + 4 = 36
Cup calculation: 36 - 32 = 4 inches difference = D cup
Result
Bra Size: 36D (US)
This means a 36-inch band with a D cup
Quick Tips
🕐 Best Time
Measure mid-morning for most accurate results
👙 What to Wear
Non-padded bra or braless for true measurements
📏 Tape Position
Keep level and parallel to floor
✨ Pro Tip
Re-measure every 6 months or after weight changes
⚠️ Common Mistakes
Band Too Large
Most common error - band provides 80% support!
Cup Too Small
Second most common - causes spillage and discomfort
Wrong Measurement
Measuring over clothes or holding breath
Never Remeasuring
Size changes with weight, age, and hormones
💡 Did You Know?
80% of women wear the wrong bra size
The band provides 80% of support, not the straps
Bra sizes can vary significantly between brands
Your bra size can change 6+ times in your lifetime
✨ How to Know If Your Bra Fits Perfectly
📏 Band Fit (80% of Support)
Band sits level all around (parallel to floor), snug on loosest hook, can fit 2 fingers underneath
Band rides up at back, slides around, breasts sag
→ Try smaller band size or sister size down
Digs into skin, leaves red marks, uncomfortable
→ Try larger band size or sister size up
🥤 Cup Fit
Breast tissue fully contained, smooth fabric, no spillage or gaps
Breast spills over top/sides, creates "quad boob", fabric wrinkles
→ Try larger cup size
Gaps at top of cup, fabric wrinkling, breasts not filling cups
→ Try smaller cup size
🎀 Strap Fit
Stay on shoulders, don't dig in, provide minimal support (band does most work)
Slip off: Tighten or try multi-way style
Dig in: Loosen or band too loose (check band size)
🎯 Center Gore & Underwire
Lies flat against sternum (between breasts)
If floating: cups too small or band too large
Follows natural breast curve, sits on ribcage (not breast tissue)
If poking: wrong size or shape
👗 Bra Styles for Different Breast Shapes
Round/Full Breasts
Full-coverage, balconette, or T-shirt bras work best
Teardrop Shaped
Demi-cup or plunge bras provide natural lift
East-West Breasts
Side support or T-shirt bras help center
Asymmetrical
Removable padding helps balance difference
Athletic/Smaller
Push-up or lightly padded adds volume
Fuller/Heavy
Minimizer, full-coverage with wide straps
Regional Bra Sizing Methods Explained
🇺🇸 US Method
Underbust + 4-5 inches
(+4 if even, +5 if odd)
1 inch = 1 cup size
Linear progression: A, B, C, D, DD...
Traditional method from 1930s-40s when bras were less stretchy
🇬🇧 UK Method
Hybrid approach
+4 for smaller, direct for larger (34+)
Double letter system
DD, E, F, FF, G, GG, H, HH...
More size options with double letters for better fit
🇪🇺 EU Method
Direct measurement in cm
No added inches, rounded to 5cm
2cm intervals between cups
More precise than 1-inch method
Considered most scientifically accurate by many experts
Scientific Note
Why different methods? The US/UK "+4 method" was developed in the 1930s-40s when bras used less elastic materials. Modern elastic fabrics don't require added inches, making the European and Indian/Asian direct measurement methods more accurate for today's bras.
Which is best? Many bra fitting experts now recommend using the direct measurement method (similar to EU/Indian/Asian) for better accuracy, especially for women who've been wearing the wrong size. However, US/UK brands still use traditional sizing, so knowing your size in each system is helpful.
💡 Our Recommendation: Calculate your size in all systems and try them on. The "best" size is the one that feels most comfortable and provides proper support. Use sister sizes for fine-tuning!
Understanding Bra Sizing
How Bra Sizing Works
Bra sizing consists of two components: the band size (number) which represents the measurement around your ribcage, and the cup size (letter) which represents the difference between your bust and band measurements. The calculation method varies by region!
Perfect Fit Tips
- •The band should provide most of the support
- •Cups should fully contain breast tissue
- •Center gore should lie flat against your chest
Size Conversion Chart
| Difference | US Cup | UK Cup | EU Cup |
|---|---|---|---|
| 1" | A | A | A |
| 2" | B | B | B |
| 3" | C | C | C |
| 4" | D | D | D |
| 5" | DD/E | DD | DD |
❓ Frequently Asked Questions
How do I measure my bra size at home?
Use a soft measuring tape to measure your underbust (band) and bust (fullest part). Wear a non-padded bra or go braless. Stand straight, breathe normally, and ensure the tape is level and snug but not tight.
What is the difference between cup size and bra size?
Cup Size (A, B, C, D, etc.) refers to the volume of your breasts, determined by the difference between bust and underbust measurements. Bra Size combines band size (number) with cup size (letter), like 34B.
What are sister sizes?
Sister sizes have the same cup volume but different band sizes. Example: 34C = 36B (size up) = 32D (size down). If your band feels too tight, try a sister size up. If too loose, try a sister size down.
How often should I recheck my bra size?
Measure every 6 months or after significant weight changes (±10 lbs), pregnancy, breastfeeding, or if your current bra feels uncomfortable. Hormonal changes and aging can also affect breast size.
What if I'm between sizes?
Try both sizes. For band: if too tight, go up a band and down a cup (34C → 36B). If too loose, go down a band and up a cup (34C → 32D). For cups: try sister sizes or different bra styles.
Can my bra size change over time?
Yes! Weight changes, pregnancy, breastfeeding, hormonal changes, aging, and even menstrual cycles can affect breast size. Regular measurements ensure the best fit.
Why do my bra straps keep slipping?
Usually indicates a loose band. The band should provide 80% of support. Try tightening straps first. If that doesn't work, you likely need a smaller band size (try sister size down).
What does it mean if my band rides up?
Band riding up at the back means it's too loose. Try fastening on a tighter hook first. If already on tightest hook, you need a smaller band size (and possibly larger cup via sister size).
Is my bra size the same in all brands?
No, sizing varies between brands and even styles within the same brand. Use our calculator as a starting point, but always try on bras before buying when possible.
What are the consequences of wearing the wrong bra size?
Discomfort, poor posture, back/neck/shoulder pain, skin irritation, red marks, breast sagging, poor support, and unflattering appearance under clothes. A well-fitting bra improves comfort and confidence.
When should I replace my bras?
Every 6-12 months depending on wear. Signs: stretched band, loose straps, worn fabric, underwire poking out, loss of support, or when on tightest hook and still loose.
How should I care for my bras?
Hand wash in cold water with gentle detergent, air dry (never in dryer), alternate bras (rest 24 hours between wears), store flat or hanging (not folded), and fasten hooks when washing to prevent snagging.