BMI Calculator
Calculate Body Mass Index and healthy weight range (Metric & Imperial)
How Does It Work?
Accurate Body Mass Index (BMI) calculator. Supports both metric (cm/kg) and imperial (ft-in/lbs) units with standard World Health Organization (WHO) categories.
WHO categories: Underweight (<18.5), Normal (18.5–24.9), Overweight (25–29.9), Obese (30+).
Real-World Worked Example
An adult male stands 178 cm (5 feet 10 inches) tall and weighs 78 kg.
- •Height in meters: 1.78 m → Height squared: 3.1684 m²
- •BMI Score: 78 / 3.1684 = 24.62
- •WHO Classification: Normal / Healthy Weight (18.5 to 24.9)
- •Healthy Weight Range for this height: 58.6 kg to 78.9 kg
Takeaway: While within WHO global normal limits, South Asian health guidelines recommend maintaining BMI below 23.0 to reduce visceral diabetes risk.
Related Guides & Calculation Deep Dives
All guidesBMI Explained: What Your Number Means (and Doesn't)
Body Mass Index (BMI) is a screening tool that compares body weight to height: BMI = weight (kg) / height (m)². A normal adult BMI range is 18.5 to 24.9 (18.5 to 22.9 for Asian populations). While useful for population screening, BMI cannot distinguish muscle from fat.
How Many Calories Should You Eat a Day?
Your daily calorie needs depend on your Basal Metabolic Rate (BMR) and activity level (TDEE). An average sedentary 30-year-old male weighing 75 kg needs roughly 2,150 calories to maintain weight, while an average female weighing 60 kg needs roughly 1,750 calories. For fat loss, a moderate deficit of 400 to 500 calories per day is optimal.
How Much Water Should You Drink Daily?
A standard baseline for daily water intake is roughly 35 ml per kilogram of body weight. An individual weighing 70 kg requires approximately 2.45 liters of water daily, with extra intake needed for hot climates and physical workouts.
BMI FAQs
Common questions, calculation formulas, and usage rules.
A BMI between 18.5 and 24.9 is considered within the healthy/normal weight range for adults.
Related Tools
BMR & Daily Calorie Calculator
Calculate Basal Metabolic Rate and daily maintenance calorie needs
Ideal Weight Calculator
Find your target healthy body weight using standard formulas (Devine, Robinson, Miller, Hamwi). Estimates only, not medical advice.
Water Intake Calculator
Calculate daily recommended hydration based on body weight and activity