BMI Calculator
BMI Calculator
Calculate your Body Mass Index (BMI) based on your height and weight. BMI is a widely used screening tool that estimates body fat and helps identify potential health risks.
Formula Used
BMI = Weight (kg) ÷ [Height (m)]²
About This Calculator
What It Does
Calculate your Body Mass Index from your height and weight. BMI is a widely-used screening tool that estimates body fat and categorizes results as underweight, normal weight, overweight, or obese.
Worked Example
A person weighing 70 kg and measuring 170 cm: height in meters = 1.70 m. BMI = 70 ÷ (1.70 × 1.70) = 70 ÷ 2.89 ≈ 24.2. This falls in the 'Normal weight' category (18.5-24.9).
Real-World Usage
Use BMI for general health screening and to track weight changes over time. It's used by doctors, nutritionists, and fitness professionals as a starting point — not a diagnosis — for health assessments.
Local Context
BMI uses the same WHO thresholds worldwide. Many countries publish their own dietary guidelines — the US issues Dietary Guidelines for Americans, the UK has the Eatwell Guide, and EU nations follow national nutrition recommendations. BMI is a screening tool, not a medical diagnosis.
Frequently Asked Questions
What BMI ranges indicate a healthy weight?
According to the WHO: below 18.5 is underweight, 18.5–24.9 is normal weight, 25–29.9 is overweight, and 30+ is obese.
Is BMI accurate for everyone?
BMI does not distinguish between muscle and fat, so very muscular individuals may be classified as overweight or obese despite having low body fat. It is one screening tool — not a diagnosis.
Should children use this BMI calculator?
No. This calculator is designed for adults aged 20 and over. Children and teens should use age- and sex-specific BMI percentiles, as their bodies are still developing.