Bra Size Converter & Calculator

Convert bra sizes between US, UK, EU, French, and Australian sizing systems. Use our band and cup size charts to find your perfect international fit, from 32A through 40DD.

Band Size Conversion

Quick Converter

I know my size in

My size

US/UK Band	EU Band	FR/ES Band	AU Band	Underbust (in)
30	65	80	8	26-27
32	70	85	10	28-29
34	75	90	12	30-31
36	80	95	14	32-33
38	85	100	16	34-35
40	90	105	18	36-37
42	95	110	20	38-39
44	100	115	22	40-41

Click any row to highlight it. Sizes are approximate and may vary by brand.

Full Bra Size Conversion (Band + Cup)

Quick Converter

I know my size in

My size

US	UK	EU	FR	AU	Bust-Band (in)
32A	32A	70A	85A	10A	1
32B	32B	70B	85B	10B	2
32C	32C	70C	85C	10C	3
32D	32D	70D	85D	10D	4
32DD	32DD	70E	85E	10DD	5
34A	34A	75A	90A	12A	1
34B	34B	75B	90B	12B	2
34C	34C	75C	90C	12C	3
34D	34D	75D	90D	12D	4
34DD	34DD	75E	90E	12DD	5
36A	36A	80A	95A	14A	1
36B	36B	80B	95B	14B	2
36C	36C	80C	95C	14C	3
36D	36D	80D	95D	14D	4
36DD	36DD	80E	95E	14DD	5
38A	38A	85A	100A	16A	1
38B	38B	85B	100B	16B	2
38C	38C	85C	100C	16C	3
38D	38D	85D	100D	16D	4
38DD	38DD	85E	100E	16DD	5
40A	40A	90A	105A	18A	1
40B	40B	90B	105B	18B	2
40C	40C	90C	105C	18C	3
40D	40D	90D	105D	18D	4
40DD	40DD	90E	105E	18DD	5

Click any row to highlight it. Sizes are approximate and may vary by brand.

How to Measure Your Bra Size

Wear a non-padded bra or no bra for the most accurate measurement. Use a soft tape measure and keep it level around your body.

Step 1: Band Size (Underbust)

Wrap the tape snugly around your ribcage, directly under your bust. The tape should be level all the way around and firm against your skin without digging in. Round to the nearest whole number. If the number is even, that is your band size. If odd, round up to the next even number.

Step 2: Cup Size (Bust)

Measure loosely around the fullest part of your bust, keeping the tape level. Subtract your band measurement from this bust measurement. The difference determines your cup size: 1 inch = A cup, 2 inches = B cup, 3 inches = C cup, 4 inches = D cup, 5 inches = DD cup.

Frequently Asked Questions

How do EU and French bra sizes differ from US sizes?

EU bra sizes use centimeter-based band numbers (65, 70, 75, etc.) instead of inches. French sizes add 15 cm to the EU band number, so an EU 70 becomes FR 85. Cup letters are mostly the same up to D, but beyond that the systems diverge: a US DD is labeled E in EU and French sizing. Italian sizing uses a completely different numbering system.

What are sister sizes and when should I use them?

Sister sizes are bra sizes that share the same cup volume but with different band lengths. For example, 34C, 32D, and 36B are all sister sizes with the same cup volume. If your usual band size feels too tight, try going up one band size and down one cup letter. If it feels too loose, go down one band size and up one cup letter.

How often should I re-measure my bra size?

Your bra size can change due to weight fluctuations, hormonal changes, pregnancy, and aging. It is recommended to re-measure every 6 to 12 months. Signs that your current size is wrong include the band riding up in the back, cups gapping or overflowing, straps digging in, or the center gore not lying flat against your sternum.

Do Australian bra sizes match UK sizes?

Australian bra cup sizes are the same as UK cup sizes, but the band sizes differ. AU band sizes use even numbers starting from 8 (equivalent to US/UK 30). To convert AU band to US/UK, multiply the AU number by a factor or use the chart above. For example, AU 10 equals US/UK 32, AU 12 equals 34, and so on, adding 22 to the AU number.