Complete BMI Guide: Normal Ranges by Age & Gender

BMI (Body Mass Index) is the most widely used method to assess whether someone is at a healthy weight. It uses a simple formula based on height and weight.

BMI Formula

BMI = Weight (kg) / Height (m)²

Example: 170cm tall, 68kg → BMI = 68 / 1.70² = 23.5

WHO International Standards

BMI Range	Classification

Below 18.5	Underweight
18.5–24.9	Normal
25.0–29.9	Overweight
30.0–34.9	Obese Class I
35.0–39.9	Obese Class II
40.0+	Obese Class III

Asian-Specific Criteria

Asians tend to have higher body fat percentage at the same BMI, so the Asia-Pacific guidelines use lower thresholds:

BMI Range	Classification (Asian)

Below 18.5	Underweight
18.5–22.9	Normal
23.0–24.9	Overweight (At Risk)
25.0–29.9	Obese Class I
30.0+	Obese Class II

Recommended BMI by Age

Age	Recommended BMI

19–24	19–24
25–34	20–25
35–44	21–26
45–54	22–27
55–64	23–28
65+	24–29

Limitations of BMI

Doesn't account for muscle mass — athletes may show high BMI despite being healthy

Ignores fat distribution — belly fat is more dangerous but BMI can't detect it

No gender differentiation — women naturally have higher body fat

Ethnic variations — body composition differs across ethnicities

Use our BMI calculator for an instant, accurate assessment.

BMI Normal Range: Complete Guide by Age and Gender