BMI Calculator
Calculate your Body Mass Index instantly — find your weight category, healthy weight range, and personalised guidance
Your BMI Result
Enter your height and weight, then click Calculate.
BMI Classification Table
| BMI Range | Category | Health Risk |
|---|---|---|
| < 18.5 | Underweight | Malnutrition, osteoporosis |
| 18.5 – 24.9 | Normal Weight | Lowest risk |
| 25.0 – 29.9 | Overweight | Moderate risk |
| 30.0 – 34.9 | Obese Class I | High risk |
| 35.0 – 39.9 | Obese Class II | Very high risk |
| ≥ 40.0 | Obese Class III | Extremely high risk |
Frequently Asked Questions
BMI (Body Mass Index) measures body fat based on height and weight. Formula: BMI = weight (kg) ÷ height² (m²). For imperial: BMI = (weight in lbs × 703) ÷ height² (inches). It was developed by Adolphe Quetelet in the 1830s.
BMI is a useful screening tool but doesn't account for muscle mass, bone density, or fat distribution. Athletes may show a high BMI due to muscle. Older adults may have a "normal" BMI with excess body fat. Always consult a doctor for a full health assessment.
For adults aged 18–65, the WHO considers a BMI of 18.5 to 24.9 healthy. Below 18.5 is underweight; 25–29.9 is overweight; 30+ is obese. For Asian populations, the WHO suggests lower thresholds (overweight at 23, obese at 27.5).
Healthy weight range = 18.5 × height² to 24.9 × height² (height in metres). For example, at 170 cm: 53.5 kg – 72.0 kg. This calculator shows your personal range automatically after calculating.
For children and teenagers (2–19), BMI is interpreted using age- and sex-specific percentiles, not fixed cutoffs. A healthy BMI percentile is between the 5th and 85th. This calculator is designed for adults — use CDC BMI-for-age charts for children.
About This BMI Calculator
This free BMI Calculator uses the standard WHO formula to instantly classify your weight. It supports both metric (cm/kg) and imperial (ft–in/lbs) inputs. You get your BMI score, health category, and the healthy weight range for your height.
Healthy Weight by Height (Metric)
| Height | Healthy Range (kg) |
|---|---|
| 155 cm | 44.5 – 59.9 kg |
| 160 cm | 47.4 – 63.7 kg |
| 165 cm | 50.3 – 67.7 kg |
| 170 cm | 53.5 – 72.0 kg |
| 175 cm | 56.7 – 76.3 kg |
| 180 cm | 60.0 – 80.7 kg |
| 185 cm | 63.3 – 85.2 kg |
Healthy Weight by Height (Imperial)
| Height | Healthy Range (lbs) |
|---|---|
| 5'0" | 97 – 130 lbs |
| 5'3" | 107 – 141 lbs |
| 5'6" | 118 – 154 lbs |
| 5'9" | 128 – 168 lbs |
| 6'0" | 140 – 183 lbs |
| 6'3" | 152 – 199 lbs |
