Bra Size Conversion: US, UK, EU, FR & AU
A complete reference for converting bra sizes across all major international systems, with measuring instructions and worked examples.
Last updated: 2026-04-28
How Bra Sizing Systems Work
Bra sizing combines two measurements: the band size (underbust circumference) and the cup size (the difference between the fullest bust measurement and the band). US and UK systems express band size in inches; EU and FR systems use centimeters with a different scale. Understanding both components is essential for accurate cross-system conversion.
Band Size Conversion Chart (28–44 inches)
| Band (inches) | Band (cm) | US / UK | EU | FR / ES | AU |
|---|---|---|---|---|---|
| 28 | 71 | 28 | 60 | 75 | 8 |
| 30 | 76 | 30 | 65 | 80 | 10 |
| 32 | 81 | 32 | 70 | 85 | 12 |
| 34 | 86 | 34 | 75 | 90 | 14 |
| 36 | 91 | 36 | 80 | 95 | 16 |
| 38 | 97 | 38 | 85 | 100 | 18 |
| 40 | 102 | 40 | 90 | 105 | 20 |
| 42 | 107 | 42 | 95 | 110 | 22 |
| 44 | 112 | 44 | 100 | 115 | 24 |
FR/ES formula: FR band = EU band + 15. So EU 75 = FR 90, EU 80 = FR 95, etc.
Cup Size Equivalents (US A–G)
| US Cup | UK Cup | EU Cup | FR Cup | Bust − Band (approx.) |
|---|---|---|---|---|
| A | A | A | A | 1 inch / 2.5 cm |
| B | B | B | B | 2 inches / 5 cm |
| C | C | C | C | 3 inches / 7.5 cm |
| D | D | D | D | 4 inches / 10 cm |
| DD / E | DD | E | E | 5 inches / 12.5 cm |
| DDD / F | E | F | F | 6 inches / 15 cm |
| G | F | G | G | 7 inches / 17.5 cm |
Cup letters align closely through D, but diverge at larger sizes. UK and US labeling differs most above DD. Always verify the specific brand's size chart when ordering above a D cup internationally.
How to Measure Your Bra Size
Step 1 — Band (Underbust) Measurement
Wrap a soft measuring tape snugly around your rib cage, directly under your bust. Keep the tape level and parallel to the floor. Record this number in inches. US and UK band sizes are usually this measurement rounded to the nearest even number.
Step 2 — Bust (Fullest Point) Measurement
Measure around the fullest part of your bust, keeping the tape level. Do not pull the tape too tight; it should skim the surface comfortably.
Step 3 — Calculate Cup Size
Subtract the band measurement from the bust measurement. Each inch of difference corresponds to one cup size: 1 inch = A, 2 inches = B, 3 inches = C, 4 inches = D, 5 inches = DD, and so on.
Worked Example: US 34B to Other Systems
- UK: 34B — identical band and cup letter.
- EU: Band 34″ = EU 75; cup B stays B. Result: EU 75B.
- FR: EU 75 + 15 = FR 90; cup B stays B. Result: FR 90B.
- AU: US band 34 = AU 14; cup B stays B. Result: AU 14B.
Use our length converter to switch between inches and centimeters when taking measurements.