Bra Size Guides, Charts & Fitting Tips for Women
Understand U.S. bra sizing, band and cup relationships, sister sizes, common fit questions, and FitMyBra size guides in one simple place.
The number represents the band size.
The letter represents cup size within that band.
A nearby size can have similar cup volume with a different band.
How Bra Sizing Works
A bra size combines a band number with a cup letter. The cup letter does not represent the same volume across every band size, so both parts should always be read together. Measurements can provide a useful starting point, while comfort and how the bra sits when worn help determine whether the fit works for you.
Start With the Basics
These four ideas make bra size charts and fit guides easier to understand.
U.S. Bra Size Chart Basics
A common starting method compares the difference between bust and band measurements.
| Bust Minus Band | Common U.S. Cup | Example With 34 Band | What It Means |
|---|---|---|---|
| 1 inch | A | 34A | About 1 inch difference |
| 2 inches | B | 34B | About 2 inches difference |
| 3 inches | C | 34C | About 3 inches difference |
| 4 inches | D | 34D | About 4 inches difference |
| 5 inches | DD / E | 34DD / 34E | Label can vary by brand |
| 6 inches | DDD / F | 34DDD / 34F | Label can vary by brand |
Bra sizing systems and cup labels can vary by brand. Use this chart as a general U.S. starting point rather than a universal sizing rule.
Band Size and Cup Size
The number and letter work together to describe a bra size.
Band Size
The band provides much of a bra's support and should sit level around the body without painful pressure.
The band may be too loose or need adjusting.
Check the size, construction, and how the band is positioned.
A secure and level band is one useful sign of a better fit.
Cup Size
Cup volume changes as band size changes. A C cup on one band size is not identical in volume to a C cup on every other band.
The cup size, shape, or bra style may not be matching comfortably.
Check whether more cup room or a different shape works better.
A smooth and comfortable cup is one useful fit signal.
Understanding Sister Sizes
Sister sizes use different band and cup combinations while keeping a similar cup volume.
Popular Bra Size Guides
Browse individual size guides already published on FitMyBra.
Popular Size Comparisons
Compare nearby bra sizes and understand how band and cup relationships change.
Common Bra Fit Questions
Start with the fit issue you notice most.
Latest Size Guides
Recently published guides from the FitMyBra Size Guides category.
Need a Starting Size?
Use a FitMyBra calculator as a starting point, then use the guides on this page to understand the result.
Bra Size Questions
Quick answers to common U.S. bra sizing and fit questions.