The BMI (Body Mass Index) Calculator is a tool that helps you assess whether your weight falls within a healthy range. By calculating your BMI using your height and weight,
you can find out whether you are in the normal weight, underweight, or overweight category. Additionally, this calculator provides product recommendations to help maintain or improve your health.
Calculator information
📋 How to use this calculator
- Select sex (male or female) - fat and muscle distribution differ even at identical BMI values.
- Enter weight in pounds or kilograms. Use the same scale consistently, ideally in the morning before eating.
- Enter height in inches or centimeters. Measure barefoot, standing tall against a wall.
- Click "Calculate BMI". The result appears with its category (underweight, normal, overweight, obese) and health guidance.
- Record the result and repeat every 2-4 weeks to track the trend rather than a single data point.
🧮 Body Mass Index (BMI) formula
BMI = weight (kg) / height^2 (m^2), or BMI = 703 x weight (lb) / height^2 (in^2)
- Weight = body weight in kilograms (or pounds)
- Height = body height in meters (or inches)
- BMI is unitless
BMI is a screening tool for the general adult population (age 20+). For children and teens, use the Child BMI calculator, which factors in age and sex.
💡 Worked example: Adult female, 132 lb (60 kg), 5'5" (165 cm)
Given:- Weight = 60 kg (132 lb)
- Height = 165 cm (5'5") = 1.65 m
Steps:- Square the height: 1.65 x 1.65 = 2.7225
- Divide weight by height squared: 60 / 2.7225 = 22.04
Result: BMI = 22.0 - normal weight (18.5-24.9). Metabolic disease risk is low at this value.
❓ Frequently asked questions
What BMI range is considered normal?
The CDC and WHO use the same adult cutoffs: underweight <18.5, normal 18.5-24.9, overweight 25.0-29.9, obesity 30.0 and above (with class I 30-34.9, class II 35-39.9, class III 40+). Adults of South Asian, East Asian, or Pacific Islander descent may face elevated cardiometabolic risk at lower thresholds (overweight at 23, obesity at 27.5).
Is BMI accurate for athletes or muscular people?
Not fully. BMI measures weight-to-height without distinguishing muscle from fat. Athletes with high muscle mass often land in the overweight category despite low body fat. In these cases, use additional measurements like body fat percentage, waist circumference, or a body composition scan (DEXA, BIA).
My BMI is normal but I have excess belly fat. What does that mean?
You may be a 'TOFI' (Thin Outside, Fat Inside) or have high visceral fat. Check waist circumference: above 40 inches for men or 35 inches for women indicates metabolic risk even with a normal BMI. See your physician for blood glucose, lipid, and blood pressure screening.
How do I lower my BMI safely?
Aim for 1-2 lb (0.5-1 kg) per week through a 500-750 kcal/day deficit plus 150 minutes/week of physical activity, in line with the Dietary Guidelines for Americans and ACSM. Don't drop BMI below 18.5 (underweight). Avoid crash diets that cost lean muscle and tend to rebound.
How often should I check my BMI?
For healthy adults, once a month is enough to track the trend. Weekly check-ins help during an active weight loss or gain program. Avoid daily weigh-ins - water and food fluctuations add noise without useful signal.
📚 Sources & references
Last updated: May 11, 2026