How it is calculated, with one example
The formula is BMI = weight in kilograms ÷ height in metres squared. For 65 kg at 1.70 m: 1.70² = 2.89, and 65 ÷ 2.89 ≈ 22.5, which sits in the normal range. Watch the units: metres rather than centimetres, kilograms rather than jin — plugging in 170 cm is the classic mistake and yields an absurd 0.0002. To get the figure and your target range directly, use the BMI calculator.
Categories for Chinese adults
| 分级Category | BMI | 说明Notes |
|---|---|---|
| 偏瘦Underweight | < 18.5 | 建议评估营养摄入Check nutrition intake |
| 正常Normal | 18.5 – 23.9 | 维持即可Maintain |
| 超重Overweight | 24.0 – 27.9 | 结合腰围判断风险Combine with waist |
| 肥胖Obese | ≥ 28.0 | 建议就医评估Consider medical advice |
WHO 国际标准的分界为 18.5 / 25 / 30，与中国标准不同：同一体重在中国标准下可能已属超重，在 WHO 标准下仍是正常。The WHO cut-offs are 18.5 / 25 / 30: the same weight may already count as overweight in the Chinese standard while still "normal" internationally.
Normal weight ranges by height
The table converts BMI 18.5–23.9 into a normal weight range, and "overweight limit" is the weight at BMI 27.9 — beyond that you enter the obese band. These are screening references rather than hard targets: a muscular person can exceed the limit with perfectly normal body fat.
| 身高Height | 正常区间Normal | 超重上限Overweight limit |
|---|---|---|
| 150 cm | 41.6 – 53.8 | 62.8 |
| 155 cm | 44.4 – 57.4 | 67.0 |
| 160 cm | 47.4 – 61.2 | 71.4 |
| 165 cm | 50.4 – 65.1 | 76.0 |
| 170 cm | 53.5 – 69.1 | 80.6 |
| 175 cm | 56.7 – 73.2 | 85.4 |
| 180 cm | 59.9 – 77.4 | 90.4 |
| 185 cm | 63.3 – 81.8 | 95.5 |
| 190 cm | 66.8 – 86.3 | 100.7 |
Waist circumference thresholds
BMI cannot see fat distribution, so waist matters too: in the Chinese standard, men at 90 cm or more and women at 85 cm or more are centrally obese (abdominal fat), and it deserves attention even when BMI looks normal. To measure: stand relaxed with feet 25–30 cm apart, and at the end of an exhale run a tape horizontally about 1 cm above the navel — snug against the skin but not compressing it. Asian populations tend to carry more visceral fat at the same BMI, which is part of why the Chinese cut-offs are stricter than the WHO’s.
Limits and correct use
Adult BMI categories do not apply to three groups: children and adolescents under 18 (who need age- and sex-specific percentiles), pregnancy and breastfeeding, and muscular athletes or regular gym-goers. BMI also cannot distinguish fat from muscle, does not reflect where fat sits, and ignores individual variation. Use it for trends rather than single readings: weigh yourself under the same conditions (morning, fasted) and watch the monthly direction. To estimate daily energy needs, try the BMR and TDEE calculator, and defer to medical check-ups and your doctor for anything health-related.
FAQ
Does a normal BMI mean I am healthy?
No. BMI only reflects the ratio of weight to height; it says nothing about body fat, muscle mass, fat distribution, blood pressure or lipids. Someone with a normal BMI but a large waist still carries metabolic risk.
Why do the Chinese and WHO cut-offs differ at the same BMI?
Research shows Asian populations develop visceral fat and metabolic problems at lower BMI values, so the Chinese standard moves the overweight and obese thresholds down to 24 and 28, while the WHO uses 25 and 30.
Can children use this table?
No. Children and adolescents under 18 need age- and sex-specific percentile curves (such as P85 and P95); fixed adult cut-offs produce false conclusions.