Body Mass Index (BMI) Reference Calculator
A body mass index (BMI) calculator evaluates weight status by dividing a person's body weight by height squared according to World Health Organization (WHO) categories. Applying the formula BMI = kg/m² or 703 × lb/in², it categorizes results into underweight, normal weight (18.5–24.9), overweight, and obesity ranges.
By Sofia Marchetti (Home & Wellness Reviewer) · Reviewed by Daniel OkoroUpdated · Published
Feet
0ft
Inches
0in
Weight
0lbs
BODY MASS INDEX (BMI)
Category: Enter values (Healthy band: 18.5 – 24.9)
How Does the BMI Calculator Calculator Work?
- Select Imperial (feet/inches, pounds) or Metric (cm, kg).
- Enter height and weight.
- View your calculated score alongside WHO reference classifications: Underweight (<18.5), Normal (18.5–24.9), Overweight (25–29.9), and Obese (≥30).
What Is the BMI Calculator Formula?
BMI = (Weight lbs × 703) / Height in² or Weight kg / Height m²
Standard demographic screening metric for adult body mass relative to height.
Variables
BMI:Body Mass Index score
Weight:Body weight in lbs or kg
Height:Stature in inches or meters
How Do You Calculate BMI Calculator Step by Step?
Adult standing 5 feet 10 inches tall (70 in) weighing 165 lbsHeight: 5 ft 10 in
Weight: 165 lbs
BMI = (165 × 703) / (70 × 70) = 115,995 / 4,900 = 23.67
23.67 falls within the WHO Normal weight category (18.5 to 24.9)
Final Solution:BMI 23.7 (Normal weight reference)
WHO adult BMI reference bands
| BMI (kg/m2) | Band | Meaning |
|---|---|---|
| Below 18.5 | Underweight | Below the healthy range |
| 18.5 - 24.9 | Healthy range | Reference healthy band |
| 25.0 - 29.9 | Overweight | Above the healthy range |
| 30.0 and above | Obesity | Clinical obesity range |
BMI Calculator Questions and Answers
BMI is an epidemiological population screening tool. It does not distinguish between muscle mass and fat mass, making it less representative for athletes, pregnant women, or muscular individuals.
Where Do These BMI Calculator Standards Come From?
Related Calculators & Converters
Daily Water Intake Calculator
Estimate your recommended daily water consumption in fluid ounces and liters based on body weight, climate, and physical activity levels.
Walking Steps to Distance and Calories
Convert your pedometer or smartwatch steps into miles, kilometers, and estimated active calories burned.