BMI Calculator
Calculate your Body Mass Index and check if you're in a healthy weight range.
Key facts
- WHO adult categories: under 18.5 underweight, 18.5–24.9 healthy (normal) weight, 25–29.9 overweight, 30 or more obese (class I 30–34.9, II 35–39.9, III 40+).
ExampleBMI for 70 kg at 175 cm
22.9
Normal weightIn the healthy weight range for your height.
- Healthy weight for your height
- 56.7–76.3 kg
- Normal weight BMI
- 18.5–24.9
General information from published research, not a diagnosis or medical advice. Talk to a doctor before changing medication or treatment. BMI can’t tell muscle from fat, and the adult categories (WHO) don’t apply under 20. Terms
How this works: Method, 1 source, Checked against 8 worked examples,
How this works
Method
BMI is your weight in kilograms divided by the square of your height in metres (pounds, feet and inches are converted first). The category uses the World Health Organization’s adult cut-offs, and the healthy weight for your height is the weight that gives a BMI of 18.5 to 24.9.
Sources
How it’s tested
8 worked examples for this page are checked by automated tests before every release: given the inputs, the tool must show the expected answer.
Limits
General information from published research, not a diagnosis or medical advice. Talk to a doctor before changing medication or treatment. BMI can’t tell muscle from fat, and the adult categories (WHO) don’t apply under 20.
Privacy
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Changes
- Added the BMI chart page: every adult height from 4 ft 10 in to 6 ft 6 in and 148 to 200 cm, with your point on the chart.
- Added a printable report with the weight scale and the categories at your height.
- Added key facts with the WHO categories; the disclaimer became one quiet line under the result.
- Redesigned: a weight ruler with your BMI marked, the healthy weight for your height, sliders for both inputs and a shareable result image.
- Added next steps that follow your result.
Frequently Asked Questions
What is BMI and how is it calculated?
Body Mass Index (BMI) is a numerical value calculated by dividing your weight in kilograms by the square of your height in meters (kg/m²). It is a widely used screening tool to categorize individuals into weight categories such as underweight, normal weight, overweight, and obese.
What are the BMI categories?
The standard BMI categories are: Underweight (below 18.5), Normal weight (18.5 to 24.9), Overweight (25 to 29.9), Obese Class I (30 to 34.9), Obese Class II (35 to 39.9), and Obese Class III (40 and above). These ranges are established by the World Health Organization.
What are the limitations of BMI?
BMI does not distinguish between muscle mass and fat mass, so muscular individuals may have a high BMI despite being healthy. It also does not account for age, sex, ethnicity, or body fat distribution. For example, abdominal fat carries greater health risks than fat stored elsewhere, but BMI cannot measure this distinction.
What is a healthy weight range?
A healthy weight range corresponds to a BMI between 18.5 and 24.9. The exact weight range depends on your height. For example, for someone who is 170 cm tall, the healthy weight range is approximately 53.5 to 72.0 kg. This calculator shows your personalized healthy weight range based on your height.
Is BMI accurate for athletes and muscular individuals?
BMI can be misleading for athletes, bodybuilders, and highly muscular individuals because muscle weighs more than fat. These individuals may be classified as overweight or obese by BMI despite having low body fat percentages. Alternative measures like body fat percentage, waist circumference, or DEXA scans provide more accurate assessments for such individuals.