BMI Calculator
Calculate Body Mass Index to assess weight status. Height, weight, BMI category classification.
How to Use
Enter your values in the fields above and click Calculate to get instant results. All computations run locally in your browser. No data is ever uploaded or stored.
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BMI Categories Reference
Underweight: BMI below 18.5 — may indicate malnutrition or other health issues.
Normal weight: BMI 18.5–24.9 — associated with lowest health risk for most people.
Overweight: BMI 25–29.9 — increased risk of heart disease, diabetes, and other conditions.
Obese: BMI 30 and above — significantly higher risk of chronic diseases.
Beyond BMI: Other Health Metrics
While BMI is a quick assessment tool, consider combining it with other measurements for a complete picture. Waist circumference, waist-to-hip ratio, body fat percentage, and blood pressure all provide valuable health information. Our related calculators — Body Fat, BMR, and Calorie calculators — can help you get a more comprehensive view of your health.
Understanding Body Mass Index
BMI (Body Mass Index) is a screening tool that estimates body fat based on height and weight. The formula is BMI = weight(kg) / height²(m²). CalcSolver's BMI calculator instantly computes your BMI and classifies it into WHO standard categories: Underweight (below 18.5), Normal (18.5–24.9), Overweight (25–29.9), and Obese (30+).
A 175cm, 70kg person has a BMI of 22.9 — firmly in the "Normal" range. The same height at 90kg gives a BMI of 29.3 (Overweight). BMI is useful for population-level analysis but has individual limitations: it doesn't account for muscle mass, bone density, or fat distribution.
For a more complete health picture, combine BMI with other metrics. Waist circumference over 40 inches (men) or 35 inches (women) indicates elevated health risk regardless of BMI. Use CalcSolver's body fat calculator, calorie calculator, and BMR calculator for a comprehensive health assessment.
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Frequently Asked Questions
What is BMI and how is it calculated?
BMI (Body Mass Index) is calculated by dividing your weight in kilograms by the square of your height in meters (kg/m²). It provides a simple numeric measure to classify underweight, normal weight, overweight, and obesity categories based on body size.
What are the standard BMI categories?
The WHO standard BMI categories are: Underweight (below 18.5), Normal weight (18.5–24.9), Overweight (25–29.9), and Obese (30 and above). These ranges apply to adults aged 20 and older, regardless of gender.
Is BMI an accurate measure of health?
BMI is a useful screening tool but has limitations. It does not distinguish between muscle mass, bone density, fat distribution, or body composition. Athletes may have a high BMI due to muscle mass. For a complete health assessment, combine BMI with other measurements like waist circumference, body fat percentage, and blood tests.
How often should I check my BMI?
For general health monitoring, checking your BMI every few months is sufficient. If you are actively working on weight management, monthly tracking can help you observe trends. Remember that BMI is just one indicator — focus on overall lifestyle habits for long-term health.