Last updated August 8, 2025
The bra as we know it today emerged from a need during World War I. 28,000 tons of steel were released after the U.S. War Industries Board asked women to stop buying metal corsets. That amount was enough for two battleships. However, some of the women’s undergarment adaptations are more recent.
The cup size is measured by the difference between band size (underbust circumference) and bust measurement. Within each cup size category, actual breast volume varies significantly based on band size. Breast or bra size measurements were categorized by different cup sizes: AA, A, B, C, DD, and DD. This alphabetical system was established in 1935 by Warner's “Alphabet Bra”. However, cup sizes above DD were not introduced until the 1990s.
Although human breasts are unique in that they are permanently enlarged and are not present only during lactation as in other mammals, 71% of women worldwide remain dissatisfied with their breast size. This creates a cultural and economic phenomenon worth over USD 99 billion around the world. Breast size varies across countries due to multiple biological and environmental factors, like genetic heritage, nutritional status, body mass index, hormones, and other factors.
The information obtained for our study was based on the AverageHeight data about cup size. Another metric present is the Female Body Mass Index (BMI). As breast tissue consists largely of fatty tissue and glands, the average BMI data from the World Health Organization can also support the understanding of rankings.
Nordic countries dominate the largest sizes. Sweden has the largest breast size with DD cup and BMI of 25. Norway follows with DD cup and 25.5 BMI. Finland (DD cup, BMI 25.9) and Russia (DD cup, BMI 25.9) tie for 3rd place. The United States completes the DD category with BMI of 28.7, higher than Nordic levels. The D cup tier is led by Switzerland, with a BMI of 23.6, followed by Austria (14.1), Denmark (24.2), the Netherlands (24.7), and Bulgaria (24.9).
| Country | Cup Size | BMI |
|---|---|---|
| Sweden | DD | 24.7 |
| Norway | DD | 25.5 |
| Finland | DD | 25.9 |
| Russia | DD | 25.9 |
| United States | DD | 28.7 |
| Switzerland | D | 23.6 |
| Austria | D | 24.1 |
| Denmark | D | 24.2 |
| Netherlands | D | 24.7 |
| Bulgaria | D | 24.9 |
Samoa has the smallest breast size with an A cup and BMI of 32.4, followed by American Samoa (A cup, BMI 33.0) and Tonga (A cup, BMI 33.1). Jordan ranks 4th (A cup, BMI 28.9), Kuwait places 5th (A cup, BMI 29.6), and Qatar 6th (A cup, BMI 29.6). Barbados ranks 7th (A cup, BMI 29.3), Saint Vincent & Grenadines (A cup, BMI 29.3) follows as 8th, Saint Lucia places 9th (A cup, BMI 29.2), and Dominica completes the smallest breast list with a A cup and BMI 29.
Asian countries like Japan (A cup, BMI 21.8), Vietnam (A cup, BMI 22), and Thailand (A cup, BMI 25.4) has A cups with lower BMI levels.
| Country | Cup Size | BMI |
|---|---|---|
| Samoa | A | 32.4 |
| American Samoa | A | 33.0 |
| Tonga | A | 33.1 |
| Jordan | A | 28.9 |
| Kuwait | A | 29.6 |
| Qatar | A | 29.6 |
| Barbados | A | 29.3 |
| Saint Vincent & Grenadines | A | 29.3 |
| Saint Lucia | A | 29.2 |
| Dominica | A | 29.0 |
