Bra Size Chart: Cup & Band
Look up cup size and band size across US, UK, EU, and JP—then use sister sizes when you need a nearby fit.
Bra size calculator →Loading bra size chart...
Bra Sister Size Chart
Sister sizes keep roughly the same cup volume while changing the band. Go down a band and up a cup (or up a band and down a cup). Brands still vary—use this as a starting point.
| Your size (US) | Common sister sizes |
|---|---|
| 32A | 30B · 34AA |
| 32B | 30C · 34A |
| 34B | 32C · 36A |
| 34C | 32D · 36B |
| 34DD | 32E · 36D |
| 36C | 34D · 38B |
| 38D | 36DD · 40C |
Example: 34C ≈ 32D ≈ 36B. If the band rides up, try a tighter sister; if cups gap, try a smaller cup sister on a nearby band.
Calculate your starting size with the bra size calculator, or learn how to measure for bra size.
About Our Bra Size Chart
This bra size chart converts between US, UK, European, and Japanese band and cup labels. Use it with your measurements—or the calculator—as a starting point. Brand cuts still vary.
For step-by-step measuring, see how to measure for bra size. For plus apparel sizing after you know your bra size, see the plus size clothing chart.
How to Use This Chart
Step 1: Take Measurements
- • Measure your underbust snugly
- • Measure your bust while standing straight
- • Measure your bust while leaning forward 90°
- • Use our calculator for weighted average
Step 2: Find Your Size
- • Look up your measurements in the chart
- • Find the corresponding size in your preferred standard
- • Consider sister sizes for better fit
- • Try on different styles and brands
Frequently Asked Questions
What is a bra cup size?
Cup size is the letter (A, B, C, D, DD…) based on how much larger your bust is than your underbust. The same letter on a different band is not the same volume—use sister sizes when you change the band.
What is bra band size?
Band size is the number (32, 34, 36, 38…) from your underbust measurement. A snug, level band should provide most of the support.
What is a bra sister size chart?
A sister size chart lists band/cup pairs with similar cup volume—for example 34C, 32D, and 36B. Use it when the cup fits but the band does not (or the reverse).
What does 34B bra size mean?
34B usually means a US band around 34 with a B cup. Common sister sizes include 32C and 36A. Confirm with measurements and the brand chart.
What is 75B bra size in US?
EU-style 75B often maps roughly to a US 34B starting point. Exact conversions vary by brand—check the calculator and try sister sizes if needed.
Why do I need to measure both standing and leaning?
Measuring both positions helps account for different breast shapes and provides a more accurate cup size calculation. Our calculator uses a weighted average (70% standing + 30% leaning) for optimal results.