BMI Calculator
Calculate your Body Mass Index — with healthy weight range and WHO category.
BMI Categories — WHO Classification
| Category | BMI Range | Health Risk |
|---|---|---|
| Severe Underweight | < 16.0 | Very High |
| Underweight | 16.0 – 18.4 | High |
| Normal Weight | 18.5 – 24.9 | Lowest |
| Overweight | 25.0 – 29.9 | Increased |
| Obese Class I | 30.0 – 34.9 | High |
| Obese Class II | 35.0 – 39.9 | Very High |
| Obese Class III | ≥ 40.0 | Extremely High |
Source: World Health Organization (WHO) Global Database on Body Mass Index.
Healthy Weight Range by Height
Normal BMI (18.5–24.9) translated to pounds for common heights.
| Height | Min Weight (lbs) | Max Weight (lbs) | Min (kg) | Max (kg) |
|---|---|---|---|---|
| 5'0" (152 cm) | 95 | 128 | 43 | 58 |
| 5'2" (157 cm) | 101 | 136 | 46 | 62 |
| 5'4" (163 cm) | 108 | 145 | 49 | 66 |
| 5'6" (168 cm) | 115 | 154 | 52 | 70 |
| 5'8" (173 cm) | 122 | 164 | 55 | 74 |
| 5'9" (175 cm) | 125 | 169 | 57 | 77 |
| 5'10" (178 cm) | 129 | 174 | 59 | 79 |
| 6'0" (183 cm) | 136 | 184 | 62 | 83 |
| 6'2" (188 cm) | 144 | 194 | 65 | 88 |
| 6'4" (193 cm) | 152 | 204 | 69 | 93 |
Frequently Asked Questions
What is a healthy BMI?
According to the WHO, a healthy BMI is 18.5 to 24.9. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is obese. These ranges apply to adults aged 18–65. For older adults (65+), some research suggests a slightly higher range of 22–27 may be protective.
How is BMI calculated?
BMI = weight in kg ÷ height in meters². In Imperial units: BMI = 703 × weight (lbs) ÷ height (inches)². A 5'9" person (69 inches) weighing 160 lbs has a BMI of 703 × 160 ÷ 4761 = 23.6 — in the normal range.
Is BMI accurate for muscular people?
No. BMI cannot distinguish between fat and muscle. A 200 lb athlete with 10% body fat has the same BMI as a 200 lb sedentary person with 30% body fat. For muscular individuals, body fat percentage using the Navy Method is a more meaningful metric.
What BMI is considered obese?
A BMI of 30 or higher is classified as obese. Class I (30–34.9) is associated with high health risk, Class II (35–39.9) with very high risk, and Class III / morbid obesity (40+) with extremely high risk of cardiovascular disease, type 2 diabetes, and other conditions.
What are the limitations of BMI?
BMI does not account for: muscle mass, fat distribution (belly fat is riskier than hip fat), ethnic differences (Asians face higher risks at lower BMIs), age, or gender. Use it as a quick screening tool — not a definitive health diagnosis.
What is BMI Prime?
BMI Prime = your BMI ÷ 25. A score of 1.0 means you're exactly at the top of the healthy range. Below 0.74 = underweight, 0.74–1.0 = normal, 1.0–1.2 = overweight, above 1.2 = obese. It's a quick way to see how far from the healthy range you are.
How do I lower my BMI?
BMI decreases when you lose weight. A 500 calorie/day deficit causes approximately 1 lb of fat loss per week. Combining a calorie-controlled diet with strength training and cardio is the most effective approach. Losing just 5–10% of body weight significantly reduces health risks.
Is BMI calculated differently for children?
Yes. For children and teens (2–19), BMI is assessed using age- and sex-specific growth charts (BMI-for-age percentiles). The same number means different things at different ages. This calculator is designed for adults 18 and older.