BMI Calculator
Calculate your Body Mass Index based on height and weight.
Inputs
Allowed range: 50 to 272
Allowed range: 10 to 600
Results
How it works
BMI = weight (kg) / height² (m). It's a quick screening tool, not a diagnosis. Normal range is 18.5–24.9.
Complete guide
Body Mass Index (BMI) is a fast way to put your weight in the context of your height. It was designed for population studies, not as a personal diagnosis, but it remains the most widely used screening number in clinics worldwide.
Standard adult categories: under 18.5 = underweight, 18.5–24.9 = normal, 25–29.9 = overweight, 30+ = obese. These cutoffs apply to adults; children and athletes need different reference charts.
BMI does not distinguish muscle from fat. A muscular athlete can score 'overweight' while having very low body fat, and an inactive adult can score 'normal' while carrying excess visceral fat. Use BMI alongside waist circumference, body fat percentage, and how you feel — not in isolation.
Frequently asked questions
- Is BMI accurate for everyone?
- No. It's misleading for very muscular people, the elderly with low muscle mass, pregnant women, and growing children. It works best as a rough screen for sedentary adults.
- What's a healthy BMI for older adults?
- Many researchers suggest 23–27 for adults over 65, since slightly higher weight is associated with better outcomes from illness in this age group.
- Should I use metric or imperial?
- Either works as long as you're consistent. This calculator uses centimeters and kilograms; the result is the same number worldwide.
- What number actually matters more than BMI?
- Waist circumference and waist-to-height ratio better reflect cardiometabolic risk. A waist over half your height is a stronger warning sign than a high BMI alone.