身體質量指數，英文為Body Mass Index，簡稱BMI，是由19世紀中期的比利時凱特勒最先提出，原來的設計是一個用於公眾健康研究的統計工具，目前用於過重與肥胖分類之簡便指數。
其定義為：BMI=體重(公斤)/身高(公尺)2
目前衛生福利部訂定之BMI值的判讀標準如下：
成人(不分性別)
理想體重範圍為18.5≦BMI＜24
體重過輕：BMI ＜ 18.5
正常範圍：18.5≦BMI＜24
異常範圍：過重：24≦BMI＜27
輕度肥胖： 27≦BMI＜30
中度肥胖：30≦BMI＜35
重度肥胖：BMI≧35
| |
男性 |
女性 |
| 年紀 |
過輕 |
正常範圍 |
過重 |
肥胖 |
過輕 |
正常範圍 |
過重 |
肥胖 |
| BMI＜ |
BMI 介於 |
BMI≧ |
BMI≧ |
BMI＜ |
BMI 介於 |
BMI≧ |
BMI≧ |
| 0.0 |
11.5 |
11.5-14.8 |
14.8 |
15.8 |
11.5 |
11.5-14.7 |
14.7 |
15.5 |
| 0.5 |
15.2 |
15.2-18.9 |
18.9 |
19.9 |
14.6 |
14.6-18.6 |
18.6 |
19.6 |
| 1.0 |
14.8 |
14.8-18.3 |
18.3 |
19.2 |
14.2 |
14.2-17.9 |
17.9 |
19.0 |
| 1.5 |
14.2 |
14.2-17.5 |
17.5 |
18.5 |
13.7 |
13.7-17.2 |
17.2 |
18.2 |
| 2.0 |
14.2 |
14.2-17.4 |
17.4 |
18.3 |
13.7 |
13.7-17.2 |
17.2 |
18.1 |
| 2.5 |
13.9 |
13.9-17.2 |
17.2 |
18.0 |
13.6 |
13.6-17.0 |
17.0 |
17.9 |
| 3.0 |
13.7 |
13.7-17.0 |
17.0 |
17.8 |
13.5 |
13.5-16.9 |
16.9 |
17.8 |
| 3.5 |
13.6 |
13.6-16.8 |
16.8 |
17.7 |
13.3 |
13.3-16.8 |
16.8 |
17.8 |
| 4.0 |
13.4 |
13.4-16.7 |
16.7 |
17.6 |
13.2 |
13.2-16.8 |
16.8 |
17.9 |
| 4.5 |
13.3 |
13.3-16.7 |
16.7 |
17.6 |
13.1 |
13.1-16.9 |
16.9 |
18.0 |
| 5.0 |
13.3 |
13.3-16.7 |
16.7 |
17.7 |
13.1 |
13.1-17.0 |
17.0 |
18.1 |
| 5.5 |
13.4 |
13.4-16.7 |
16.7 |
18.0 |
13.1 |
13.1-17.0 |
17.0 |
18.3 |
| 6.0 |
13.5 |
13.5-16.9 |
16.9 |
18.5 |
13.1 |
13.1-17.2 |
17.2 |
18.8 |
| 6.5 |
13.6 |
13.6-17.3 |
17.3 |
19.2 |
13.2 |
13.2-17.5 |
17.5 |
19.2 |
| 7.0 |
13.8 |
13.8-17.9 |
17.9 |
20.3 |
13.4 |
13.4-17.7 |
17.7 |
19.6 |
| 7.5 |
14.0 |
14.0-18.6 |
18.6 |
21.2 |
13.7 |
13.7-18.0 |
18.0 |
20.3 |
| 8.0 |
14.1 |
14.1-19.0 |
19.0 |
21.6 |
13.8 |
13.8-18.4 |
18.4 |
20.7 |
| 8.5 |
14.2 |
14.2-19.3 |
19.3 |
22.0 |
13.9 |
13.9-18.8 |
18.8 |
21.0 |
| 9.0 |
14.3 |
14.3-19.5 |
19.5 |
22.3 |
14.0 |
14.0-19.1 |
19.1 |
21.3 |
| 9.5 |
14.4 |
14.4-19.7 |
19.7 |
22.5 |
14.0 |
14.1-19.3 |
19.3 |
21.6 |
| 10 |
14.5 |
14.5-20.0 |
20.0 |
22.7 |
14.3 |
14.3-19.7 |
19.7 |
22.0 |
| 10.5 |
14.6 |
14.6-20.3 |
20.3 |
22.9 |
14.4 |
14.4-20.1 |
20.1 |
22.3 |
| 11 |
14.8 |
14.8-20.7 |
20.7 |
23.2 |
14.7 |
14.7-20.5 |
20.5 |
22.7 |
| 11.5 |
15.0 |
15.0-21.0 |
21.0 |
23.5 |
14.9 |
14.9-20.9 |
20.9 |
23.1 |
| 12 |
15.2 |
15.2-21.3 |
21.3 |
23.9 |
15.2 |
15.2-21.3 |
21.3 |
23.5 |
| 12.5 |
15.4 |
15.4-21.5 |
21.5 |
24.2 |
15.4 |
15.4-21.6 |
21.6 |
23.9 |
| 13 |
15.7 |
15.7-21.9 |
21.9 |
24.5 |
15.7 |
15.7-21.9 |
21.9 |
24.3 |
| 13.5 |
16.0 |
16.0-22.2 |
22.2 |
24.8 |
16.0 |
16.0-22.2 |
22.2 |
24.6 |
| 14 |
16.3 |
16.3-22.5 |
22.5 |
25.0 |
16.3 |
16.3-22.5 |
22.5 |
24.9 |
| 14.5 |
16.6 |
16.6-22.7 |
22.7 |
25.2 |
16.5 |
16.5-22.7 |
22.7 |
25.1 |
| 15 |
16.9 |
16.9-22.9 |
22.9 |
25.4 |
16.7 |
16.7-22.7 |
22.7 |
25.2 |
| 15.5 |
17.2 |
17.2-23.1 |
23.1 |
25.5 |
16.9 |
16.9-22.7 |
22.7 |
25.3 |
| 16 |
17.4 |
17.4-23.3 |
23.3 |
25.6 |
17.1 |
17.1-22.7 |
22.7 |
25.3 |
| 16.5 |
17.6 |
17.6-23.4 |
23.4 |
25.6 |
17.2 |
17.2-22.7 |
22.7 |
25.3 |
| 17 |
17.8 |
17.8-23.5 |
23.5 |
25.6 |
17.3 |
17.3-22.7 |
22.7 |
25.3 |
| 17.5 |
18.0 |
18.0-23.6 |
23.6 |
25.6 |
17.3 |
17.3-22.7 |
22.7 |
25.3 |