Bra Cup Size Chart and Sister Sizes: Complete Sizing Guide
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Understanding Bra Cup Sizes
Use this bra cup size chart to find your perfect fit based on underbust and bust measurements (in inches):
| Underbust | Band Size | Bust Measurement | Cup Size |
|---|---|---|---|
| 28" | 28 | 29" | A |
| 30" | 30 | 32" | B |
| 32" | 32 | 34" | C |
| 34" | 34 | 36" | D |
| 36" | 36 | 38" | DD/E |
Bra Sister Sizes Conversion Chart
Sister sizes are alternative sizes that maintain the same cup volume with different band lengths:
| Original Size | Sister Size Down | Sister Size Up |
|---|---|---|
| 32C | 30D | 34B |
| 34D | 32DD | 36C |
| 36E | 34F | 38DD |
| 38F | 36FF | 40E |
How to Use Sister Sizes
- If band feels tight: Go up band size + down cup size (34C → 36B)
- If band feels loose: Go down band size + up cup size (36D → 34DD)
- Always prioritize cup volume equivalence
Key Takeaways
- Measure underbust snugly for band size
- Calculate cup size using bust measurement
- Use sister sizes for comfort adjustments
