BMI Calculator

Calculate your Body Mass Index (BMI) instantly. Check your weight category with a visual gauge. Supports metric (kg/cm) and imperial (lbs/ft).

BMI RangeCategoryHealth Risk
<18.5UnderweightNutritional deficiency
18.5–24.9Normal WeightLow Risk ✓
25–29.9OverweightModerate Risk
30–34.9Obese (Class I)High Risk
35+Obese (Class II/III)Very High Risk

What is BMI and Why It Matters

Body Mass Index (BMI) is a screening tool calculated from weight and height to assess whether a person falls into a healthy weight range. While BMI doesn't directly measure body fat, it correlates with health risks like diabetes, heart disease, and hypertension. Our free BMI calculator supports both metric (kg/cm) and imperial (lbs/ft/in) units and provides instant categorization and health insights.

How to Use This Calculator

Metric: Enter weight in kilograms and height in centimeters. Imperial: Enter weight in pounds and height as feet and inches. The calculator shows your BMI, category, and health risk level. Note: BMI doesn't account for muscle mass, so athletes may have a higher BMI despite low body fat.

Frequently Asked Questions

What is the normal BMI range?
The WHO defines 18.5–24.9 as normal/healthy weight for adults. For South Asians, some guidelines suggest 18.5–22.9 due to differences in body composition and metabolic risk.
How do I calculate BMI manually?
Metric: BMI = Weight (kg) ÷ Height² (m). Example: 70 kg ÷ (1.70 m)² = 24.2. Imperial: BMI = Weight (lbs) ÷ Height² (inches) × 703. This calculator does it instantly.
Can BMI be inaccurate?
Yes. BMI doesn't account for muscle mass, bone density, or fat distribution. Athletes with high muscle may have a high BMI but low body fat. It's a screening tool, not a diagnostic measure.
What is the healthy weight range for a specific height?
For a healthy BMI of 18.5–24.9: At 5'6" (168 cm), healthy weight is 50–75 kg (110–165 lbs). Use this calculator to find your healthy range by adjusting weight until BMI falls in the green zone.
When should I consult a doctor about my BMI?
If your BMI is below 18.5 (underweight) or above 25 (overweight/obese), consult a healthcare provider. They can assess your individual health risk and recommend lifestyle changes or interventions.