Complete bra size charts for all major sizing systems. Convert between US, UK, EU, French, and Australian sizes, find your cup size from measurements, and understand sister sizes. Find your cup size by subtracting your band size from your bust measurement. The difference in inches determines your cup. Convert your underbust measurement to band size. Band sizes come in even numbers. Convert your bra size between different countries' sizing systems. Sister sizes have equivalent cup volumes with different band sizes. Use when your exact size is unavailable or a brand runs small/large. When a brand runs large, bands are stretchy, or you want more support. When a brand runs small, bands are firm, or you want more comfort. Some bralettes and sports bras use alpha sizing (S, M, L). Here's how they typically convert: Use our calculator to find your perfect fit in seconds.
Cup Size Chart
Difference (Bust - Band)
US Cup
UK Cup
EU Cup
0-1" AA AA AA 1" A A A 2" B B B 3" C C C 4" D D D 5" DD / E DD E 6" DDD / F E F 7" G F G 8" H FF H 9" I G I 10" J GG J 11" K H K 12" L HH L 13" M J M 14" N JJ N Band Size Chart
Underbust (inches)
Underbust (cm)
US/UK Band
EU Band
FR Band
25-26" 63-67 cm 28 60 75 27-28" 68-72 cm 30 65 80 29-30" 73-77 cm 32 70 85 31-32" 78-82 cm 34 75 90 33-34" 83-87 cm 36 80 95 35-36" 88-92 cm 38 85 100 37-38" 93-97 cm 40 90 105 39-40" 98-102 cm 42 95 110 41-42" 103-107 cm 44 100 115 43-44" 108-112 cm 46 105 120 45-46" 113-117 cm 48 110 125 47-48" 118-122 cm 50 115 130 International Bra Size Conversion
Cup Size Conversion
US
UK
EU
France
Australia
Japan
AA AA AA AA AA AA A A A A A A B B B B B B C C C C C C D D D D D D DD DD E E DD E DDD / F E F F E F G F G G F G H FF H H FF H I G I I G I J GG J J GG J K H K K H K Quick Conversion Examples
Which Sizing System Does My Brand Use?
Sister Size Chart
Smaller Band ↓ Larger Cup
Your Size
Larger Band ↑ Smaller Cup
28D 30C 32B 28DD 30D 32C 30D 32C 34B 30DD 32D 34C 32D 34C 36B 32DD 34D 36C 32DDD 34DD 36D 34DD 36D 38C 34DDD 36DD 38D 36DD 38D 40C 36DDD 38DD 40D 38DDD 40DD 42D When to Use Sister Sizes
Go Down a Band / Up a Cup
Go Up a Band / Down a Cup
S/M/L Size Conversion
Alpha Size
Band Size Range
Typical Bra Sizes
XS 28-30 28A-30B S 30-32 30B-32C M 32-34 32C-34D L 34-36 34D-36DD XL 36-38 36DD-38DDD XXL 38-40 38DDD-40G 3XL 40-42 40G-42H Not Sure of Your Size?
Size Charts
Note: US brands use DD, DDD, then continue with single letters (G, H, I). UK brands use double letters after single letters (DD, E, F, FF, G, GG, H, HH, J, JJ, K).
Tip: If your measurement falls between sizes, try both. Some prefer a firmer fit (smaller band) while others prefer more comfort (larger band).
US 34DDD
→
UK 34E
UK 32FF
→
US 32H
US 36G
→
EU 80G
EU 75D
→
US 34D
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Important: Alpha sizes vary significantly by brand. Always check the specific brand's size chart. These sizes work best for those with proportional bust-to-band ratios.