Health & Fitness
BMI Calculator
Calculate your Body Mass Index, healthy weight range, ideal weight, and waist-to-height ratio.
Your BMI
24.4
Healthy weight
BMI 18.5–24.9. Associated with the lowest health risk for most adults.
Healthy weight range
Healthy range for your height
129–174lb
Ideal weight (Devine formula)
161lb
How BMI works
Body Mass Index (BMI) is a quick screening tool that compares your weight to your height. It was developed by Adolphe Quetelet in the 1830s and is now used by the World Health Organization, CDC, and most clinicians as a first-pass indicator of weight-related health risk.
BMI does have limits — it does not measure body composition, so muscular people may score high without health risk, and older adults may score "healthy" while having too little muscle. We add waist-to-height ratio (a better metabolic risk marker) and ideal weight as bonus context.
Frequently Asked Questions
What is a healthy BMI?▾
A healthy BMI for most adults is between 18.5 and 24.9. Below 18.5 is considered underweight; 25–29.9 is overweight; 30+ is obese. BMI is a screening tool, not a diagnosis.
How is BMI calculated?▾
BMI = weight (kg) ÷ height (m)². For imperial units: BMI = (weight in lbs × 703) ÷ (height in inches)². The formula is the same worldwide, used by the WHO, CDC, and NIH.
Is BMI accurate for athletes?▾
Not always. BMI does not distinguish muscle from fat. Highly muscular people (athletes, lifters) may have a high BMI but low body fat. For better accuracy, combine BMI with body fat percentage and waist-to-height ratio.
What is waist-to-height ratio?▾
Your waist circumference divided by your height. A ratio under 0.5 is associated with low cardiovascular risk; 0.5–0.6 is moderate; 0.6+ is high. It is often a better predictor of metabolic risk than BMI alone.
What is ideal weight?▾
We use the Devine formula (1974), commonly cited in clinical settings. It estimates a baseline weight from your sex and height. It is a rough guide — your ideal weight depends on your body composition, muscle mass, and goals.