Calculate your Body Mass Index (BMI) instantly. Enter your height and weight to see whether you fall in the underweight, normal, overweight, or obese range according to standard adult BMI categories.
Your Measurements
What Is a BMI Calculator?
A BMI calculator (Body Mass Index calculator) is a simple tool that estimates body fat based on height and weight. It is widely used as a quick screening method for adults to see whether their weight falls into underweight, normal, overweight, or obese categories. This free BMI calculator for adults on www.usacalc.online uses the standard formula recognized by health organizations.
How BMI Is Calculated
The formula is:
BMI = weight (kg) / [height (m)]²
Or in imperial units: BMI = 703 × weight (lbs) / [height (in)]²
Once calculated, the number is compared to standard adult categories:
- Underweight: BMI less than 18.5
- Normal weight: BMI 18.5 – 24.9
- Overweight: BMI 25 – 29.9
- Obesity: BMI 30 or higher
Limitations of BMI
BMI is a useful population-level screening tool, but it has limitations. It does not distinguish between muscle and fat, so athletes or very muscular people may show a high BMI even with low body fat. It also does not account for age, sex, or fat distribution. Always use BMI as one piece of information and consult a healthcare professional for a complete health assessment.
5′10″ (178 cm) and 170 lbs (77 kg)
Why Track Your BMI?
Monitoring BMI over time can help you notice trends in weight relative to height. Combined with other measures (waist circumference, body fat percentage, fitness level), it gives a fuller picture of health. This free body mass index calculator makes it easy to check your number anytime.