Calculate your Body Mass Index instantly with waist-to-height ratio for more accurate health assessment
Using our free BMI calculator is simple. Enter your weight in pounds and height in inches. For a more accurate health assessment, add your waist measurement—waist-to-height ratio is a better predictor of health risks than BMI alone.
Select your gender and age, then click "Calculate BMI" to get your results instantly. The calculator uses the standard BMI formula: (weight in pounds ÷ height in inches²) × 703.
Tip: Measure your waist at the narrowest point between your hips and ribs, usually just above your belly button. Use a flexible measuring tape for accuracy.
Let's walk through a real example:
Now let's compare with a different scenario:
Key insight: Even with a "normal" BMI, a large waist circumference can indicate higher health risks. The waist-to-height ratio adds important context.
BMI is a widely-used screening tool that helps identify weight categories that may lead to health problems:
However, BMI has limitations. It doesn't distinguish between muscle and fat. Athletes with high muscle mass may have a high BMI but be perfectly healthy. This is why we include waist-to-height ratio for a more complete picture.
| BMI | Category | Health Risk |
|---|---|---|
| Below 18.5 | Underweight | Malnutrition, osteoporosis |
| 18.5 - 24.9 | Normal weight | Low risk |
| 25 - 29.9 | Overweight | Moderate risk |
| 30 - 34.9 | Obesity Class I | High risk |
| 35 - 39.9 | Obesity Class II | Very high risk |
| 40+ | Obesity Class III | Extremely high risk |
Waist-to-Height Ratio:
The formula is: BMI = (weight in pounds ÷ height in inches²) × 703. For example, a 170-pound person who is 70 inches tall: (170 ÷ 4900) × 703 = 24.5. Remember to square the height first!
A BMI between 18.5 and 24.9 is considered normal or healthy for most adults. However, individual health should be assessed by a healthcare provider, not BMI alone. Other factors like blood pressure, cholesterol, and blood sugar matter too.
No—BMI is a general screening tool that doesn't account for muscle mass, bone density, or body composition. Athletes, especially those who lift weights, may have a high BMI due to muscle but be in excellent health. Use waist-to-height ratio for a better assessment.
Waist circumference measures abdominal fat, which is more dangerous than fat stored in hips and thighs. visceral fat around organs increases risk for heart disease and diabetes. Men with waists over 40 inches and women over 35 inches have higher health risks.
BMI is just one screening tool, not a diagnosis. If your BMI is overweight but you have no other risk factors (normal blood pressure, cholesterol, blood sugar, active lifestyle), you may be healthy. Consult your doctor for a complete assessment. Focus on overall health, not just a number.