Cup Size Calculator | Find Your Bra Cup Size Instantly
Enter your band and bust measurements to instantly calculate your bra cup size. Understand what your cup letter really means and how it's determined.
What Is Bra Cup Size?
Cup size represents the difference between your bust measurement and band measurement. Each letter (A, B, C, etc.) represents approximately 1 inch of difference. This simple calculation determines your cup size in every sizing system worldwide.
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Enter your measurements in inches below
Your Cup Size
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Cup Size Chart
| Cup | Difference (Bust - Band) | Description |
|---|---|---|
| A | 1 inch | Small bust. 1 inch difference between bust and band. |
| B | 2 inch | Small to medium bust. 2 inch difference between bust and band. |
| C | 3 inch | Medium bust. 3 inch difference between bust and band. |
| D | 4 inch | Full bust. 4 inch difference between bust and band. |
| DD | 5 inch | Full to large bust. 5 inch difference between bust and band. |
| E | 6 inch | Large bust. 6 inch difference between bust and band. |
| F | 7 inch | Very large bust. 7 inch difference between bust and band. |
| G | 8 inch | Extra large bust. 8 inch difference between bust and band. |
How Cup Size Is Calculated
The calculation is simple: subtract your band measurement from your bust measurement. Each inch of difference corresponds to one cup size letter.
- Measure your band size: Wrap a measuring tape snugly around your ribcage, directly under your bust. Round to the nearest whole number.
- Measure your bust size: Measure around the fullest part of your bust, keeping the tape parallel to the floor.
- Subtract and match: Bust minus band = cup size difference. 1 inch = A, 2 inches = B, 3 inches = C, and so on.
Frequently Asked Questions
How do I calculate my cup size?
Subtract your band measurement from your bust measurement. The difference in inches determines your cup: 1 inch = A, 2 = B, 3 = C, 4 = D, 5 = DD/E, 6 = DDD/F, 7 = G.
What does my cup size actually mean?
Your cup size represents the volume difference between your bust and ribcage. It's not an absolute size — a 34C and 36C have different cup volumes because the band size changes the proportions.
How do I measure for cup size at home?
You need a soft measuring tape. Measure your band size around your ribcage under your bust (snug) and your bust at the fullest point. The difference between these two numbers gives your cup size.
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