BMI Calculator
Calculate BMI, BMR, body fat estimate & ideal weight range
Your BMI
24.2
✅ Normal Weight
BMI Scale
Ideal Weight
53-72 kg
BMR (Rest)
1643 cal/day
Body Fat (est.)
18.6%
Daily Calories
2546 cal
Daily Calorie Needs by Activity
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📖 Learn More About BMI Calculator
How BMI Calculator Works
Body Mass Index (BMI) is the most widely used screening tool for assessing weight relative to height. Developed by Belgian mathematician Adolphe Quetelet in the 1830s and adopted by the World Health Organization as a global standard, BMI provides a quick, cost-free estimate of whether a person's weight may be putting their health at risk.
Our BMI calculator goes beyond just the BMI number — it also computes your BMR (Basal Metabolic Rate) using the clinically validated Mifflin-St Jeor equation, an estimated body fat percentage, your ideal weight range, and daily calorie requirements for five activity levels. All of these metrics together give you a comprehensive picture of your current health status.
Important note for Indian users: Research consistently shows that South Asians develop obesity-related conditions (diabetes, cardiovascular disease, hypertension) at BMI levels lower than Western populations. The International Obesity Task Force recommends BMI cutoffs of 23 (overweight) and 27.5 (obese) for Asians, compared to 25 and 30 for Western populations. This means a BMI of 24 that seems "normal" on the scale could indicate elevated health risk for an Indian individual.
📐 BMI & BMR Formulas
BMI Formula:
BMR Formula (Mifflin-St Jeor):
Men: BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5
Women: BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161
📝 Worked Example:
Person: Male, Age 30, Weight 75 kg, Height 175 cm (1.75 m)
BMI = 75 ÷ (1.75)² = 75 ÷ 3.0625 = 24.5 (Normal Weight ✅)
BMR = (10×75) + (6.25×175) − (5×30) + 5 = 750 + 1093.75 − 150 + 5 = 1,698 calories/day
Moderately active daily calories = 1,698 × 1.55 = 2,632 calories/day
Ideal weight range = 18.5–24.9 × (1.75)² = 56.6 kg – 76.3 kg
BMI Categories — WHO vs Asian Standards
| Category | WHO (Western) | Asian Standard | Health Risk |
|---|---|---|---|
| Underweight | < 18.5 | < 18.5 | Moderate |
| Normal Weight | 18.5 – 24.9 | 18.5 – 22.9 | Low |
| Overweight | 25.0 – 29.9 | 23.0 – 27.4 | Elevated |
| Obese Class I | 30.0 – 34.9 | 27.5 – 32.4 | High |
| Obese Class II+ | 35.0+ | 32.5+ | Very High |
💡 Tips to Achieve & Maintain Healthy BMI
🥗 Focus on Food Quality, Not Just Calories
A 500-calorie meal of dal-sabzi-roti is nutritionally far superior to a 500-calorie burger. Prioritize whole grains (brown rice, millets), legumes (dal, rajma, chhole), vegetables, and fruits. Reduce refined carbs, sugar, processed foods, and fried snacks. Indian traditional diet is inherently healthy — it's the modern processed food additions that cause weight gain.
🏃 Exercise: Combine Cardio + Strength Training
For weight loss: 150-300 min/week moderate cardio (brisk walking, cycling, swimming) plus 2 days strength training. Strength training is crucial — it builds muscle, which burns more calories at rest. Even 30-minute daily walks at 5 km/h burn 150-200 calories and improve insulin sensitivity. Consistency over intensity — 30 min daily beats 2 hours once a week.
😴 Sleep: The Overlooked Weight Factor
Less than 7 hours of sleep increases ghrelin (hunger hormone) and decreases leptin (satiety hormone), making you eat 300-500 extra calories next day. Studies show sleep-deprived people are 55% more likely to be obese. Fix sleep first if you're struggling with weight. Aim for 7-9 hours. Avoid screens 1 hour before bed. Good sleep also improves gym performance and recovery.
💧 Hydration: Often Confused with Hunger
Drink 2.5-3 liters of water daily. Many times what feels like hunger is actually thirst — drink a glass of water first and wait 10 minutes. Drinking 500 ml water before meals reduces caloric intake by 13%. Avoid sugary drinks (soft drinks, packaged juices) — a 350 ml cola has 150 calories and 39g sugar. Replace with plain water, coconut water, or chaas (buttermilk).
📏 Monitor Waist, Not Just Weight
BMI doesn't tell where fat is stored. Visceral fat (around organs, shown by waist circumference) is far more dangerous than subcutaneous fat (under skin). Health risk: Men: waist > 90 cm (35 inches), Women: waist > 80 cm (31.5 inches). Measure waist every month — it's a better indicator of health improvement than weight alone. Yoga and core exercises specifically reduce visceral fat.
🎯 Set Realistic Goals: 0.5 kg/week
Sustainable weight loss is 0.5-0.75 kg/week. Faster loss causes muscle loss, nutrient deficiencies, and rebound. Don't skip meals — it leads to overeating later. Don't eliminate entire food groups (carbs are not the enemy). Track progress using BMI + photos + measurements — the scale alone is misleading (muscle weighs more than fat). Celebrate small wins every 5 kg.
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Frequently Asked Questions
What is BMI and how is it calculated?
BMI (Body Mass Index) is a numerical value calculated from your weight and height. BMI = Weight (kg) ÷ [Height (m)]². For example, if you weigh 70 kg and are 170 cm (1.70 m) tall: BMI = 70 ÷ (1.70)² = 70 ÷ 2.89 = 24.2. This is within the normal range (18.5–24.9). BMI is used as a screening tool by doctors, nutritionists, and health organizations worldwide to assess weight-related health risk.
What is a healthy BMI for Indians?
The standard WHO BMI categories (18.5–24.9 = normal) were developed for Western populations. Research shows that South Asians (Indians) tend to develop obesity-related health problems at lower BMI levels due to higher body fat percentage at the same BMI. The World Health Organization and Indian health bodies suggest: Under 18.5 = Underweight, 18.5–22.9 = Normal for Asians, 23.0–24.9 = Overweight (at risk), 25.0+ = Obese for Asians. A BMI of 23-25 that seems 'normal' by Western standards may carry health risk for Indians.
Is BMI accurate for measuring body fat?
BMI is a useful population-level screening tool, but has several limitations: (1) Doesn't distinguish muscle from fat — bodybuilders and athletes may have high BMI but very low body fat, (2) Doesn't account for age — older adults lose muscle mass, so BMI may underestimate fat %, (3) Doesn't account for body fat distribution — abdominal fat (visceral fat) is more dangerous than subcutaneous fat, (4) Gender differences — women naturally have higher body fat at the same BMI. For a more complete picture, use BMI alongside waist circumference, body fat %, and consult a doctor.
What is BMR and how is it used?
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest just to maintain basic functions — breathing, circulation, cell production. This calculator uses the Mifflin-St Jeor equation (most accurate formula): For men: BMR = 10W + 6.25H - 5A + 5. For women: BMR = 10W + 6.25H - 5A - 161 (W=weight in kg, H=height in cm, A=age). To find daily calorie needs, multiply BMR by activity level: Sedentary ×1.2, Lightly active ×1.375, Moderately active ×1.55, Very active ×1.725.
How to lose weight with a healthy BMI in mind?
To move from overweight to normal BMI: A caloric deficit of 500-750 calories/day leads to 0.5-0.75 kg weight loss per week — a sustainable pace. Combine: (1) Reduce caloric intake by 300-400 calories (avoid refined carbs, sugar, fried foods), (2) Exercise 30-45 minutes daily (mix cardio and strength training), (3) Eat more protein (keeps you full, preserves muscle), (4) Get 7-8 hours of sleep (poor sleep increases hunger hormones). Crash diets that drop 1-2 kg/week cause muscle loss and rebound weight gain — avoid them.
What is the ideal weight for my height?
Ideal weight is calculated using normal BMI range (18.5–24.9): Ideal Weight Min (kg) = 18.5 × (height in meters)². Ideal Weight Max (kg) = 24.9 × (height in meters)². Example: For 170 cm height — Ideal weight = 18.5 × 2.89 = 53.5 kg to 24.9 × 2.89 = 71.9 kg. Our calculator shows your personal ideal weight range based on your actual height. For Asian Indians, the target is the lower end of the range (BMI ~22-23).
What does body fat percentage estimate mean?
This calculator estimates body fat % using the Deurenberg formula: Body Fat % = 1.20 × BMI + 0.23 × Age - 16.2 (men) or 1.20 × BMI + 0.23 × Age - 5.4 (women). Healthy ranges: Men: 10-20%, Women: 18-28%. Athletes: Men 6-13%, Women 14-20%. Obese: Men 25%+, Women 32%+. Note: This is an ESTIMATE. DEXA scan or hydrostatic weighing are more accurate methods for precise body fat measurement.
What is waist-to-height ratio and is it better than BMI?
Waist-to-height ratio (WHtR) is considered a better predictor of cardiovascular disease risk than BMI because it measures abdominal fat directly. WHtR = Waist circumference ÷ Height. Healthy target: WHtR < 0.5 (i.e., your waist should be less than half your height). For a 170 cm person: waist should be under 85 cm (33.5 inches). For Indians specifically, waist circumference > 90 cm for men and > 80 cm for women signals metabolic risk.
How many calories should I eat per day to maintain my weight?
Your daily calorie need = BMR × Activity Multiplier. Activity levels: Sedentary (desk job, no exercise): BMR × 1.2. Lightly active (walk 1-3 days/week): BMR × 1.375. Moderately active (exercise 3-5 days): BMR × 1.55. Very active (hard exercise 6-7 days): BMR × 1.725. Athlete: BMR × 1.9. This calculator shows all five levels simultaneously. To lose weight: eat 300-500 calories below this maintenance level.
Can children use this BMI calculator?
This calculator uses adult BMI standards (WHO categories for 20+ years). For children and teenagers (2-19 years), BMI is interpreted differently using BMI-for-age percentiles: Underweight: below 5th percentile, Healthy: 5th-85th percentile, Overweight: 85th-95th percentile, Obese: above 95th percentile. The CDC and Indian Pediatrics Association provide age-and-sex specific growth charts for children. Always consult a pediatrician for children's weight assessment.