Complete Bra Size Guide
Understanding Bra Sizing
Bra sizing consists of two components: the band size (the number) and the cup size (the letter). Together, they create your bra size, such as 34B or 36DD.
Diagram showing how band size and cup size work together to create your bra size
Band Size
The band size is the measurement around your ribcage, just under your bust. This number provides the foundation of support for your bra. A properly fitting band should be snug but comfortable, and should stay parallel to the ground all the way around your body.
How Band Sizing Works
In the US and UK sizing systems:
- If your underbust measurement is an even number, that's typically your band size
- If your underbust measurement is an odd number, round up or down to the nearest even number
- Some fitting methods recommend adding 4 inches to the underbust measurement, but modern bra experts often advise against this
| Underbust Measurement (inches) | Recommended Band Size |
|---|---|
| 26-27 | 28 |
| 28-29 | 30 |
| 30-31 | 32 |
| 32-33 | 34 |
| 34-35 | 36 |
| 36-37 | 38 |
| 38-39 | 40 |
| 40-41 | 42 |
Cup Size
The cup size represents the difference between your band measurement and your bust measurement (measured at the fullest part of your bust). Each inch of difference typically corresponds to one cup size.
How Cup Sizing Works
In the US and UK sizing systems:
| Difference (Bust - Band) | US Cup Size | UK Cup Size |
|---|---|---|
| Less than 1" | AA | AA |
| 1" | A | A |
| 2" | B | B |
| 3" | C | C |
| 4" | D | D |
| 5" | DD/E | DD |
| 6" | DDD/F | E |
| 7" | G | F |
| 8" | H | FF |
| 9" | I | G |
| 10" | J | GG |
International Size Conversions
Bra sizes vary by country. Here's a quick reference for converting between different sizing systems:
| US | UK | EU | FR | IT | AU/NZ |
|---|---|---|---|---|---|
| 32A | 32A | 70A | 85A | 1A | 10A |
| 34B | 34B | 75B | 90B | 2B | 12B |
| 36C | 36C | 80C | 95C | 3C | 14C |
| 38D | 38D | 85D | 100D | 4D | 16D |
| 40DD/E | 40DD | 90E | 105E | 5E | 18DD |
Signs Your Bra Doesn't Fit Properly
Even with the right size, not all bra styles will fit every body type. Here are some common signs that your bra doesn't fit properly:
Band Issues
- Band rides up in the back
- Band feels too tight or leaves marks
- Band feels loose on the tightest hook when new
- Band doesn't stay parallel to the ground
Cup Issues
- Breast tissue spills out of the top or sides
- Cups wrinkle or gap
- Underwire sits on breast tissue
- Center gore doesn't lie flat against sternum
Strap Issues
- Straps dig into shoulders
- Straps constantly slip off
- Need to tighten straps to maximum
- Straps cause pain or discomfort
Comfort Issues
- Bra shifts or moves throughout the day
- Underwire pokes or pinches
- Constant adjusting needed
- Discomfort when sitting or moving
Finding Your Perfect Fit
Remember that our calculator provides a starting point. For the best fit:
- Try on multiple sizes around your calculated size
- Try different styles, as some may work better for your breast shape
- Consider professional bra fitting at a specialty lingerie store
- Remember that sizes can vary between brands
- Focus on how the bra feels and supports, not just the size on the label
Pro Tip
When trying on a new bra, always fasten it on the loosest hook. As the bra stretches over time, you can move to the tighter hooks to maintain the proper fit.
Next Steps
Now that you understand bra sizing, check out our other resources:
- Measuring Tips - Learn how to measure yourself accurately
- Bra Styles Explained - Find the right style for your shape and needs
- Frequently Asked Questions - Get answers to common bra fitting questions