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Optional: For BMR, TDEE & Ideal Weight
📊 Your Health Metrics
Enter your weight and height to see your BMI, category, BMR, TDEE, ideal weight range, and personalised health insights.
⚖️ Free BMI Calculator — Body Mass Index, BMR & TDEE
Calculate your Body Mass Index (BMI) with WHO-based categories, plus Basal Metabolic Rate (BMR), Total Daily Energy Expenditure (TDEE), ideal weight range, and daily calorie needs — all in one tool.
What is a BMI calculator? A BMI (Body Mass Index) calculator measures body fat based on height and weight to classify adults as underweight, normal, overweight, or obese. According to the World Health Organization (WHO), more than 1.9 billion adults worldwide are overweight, and 650 million are obese — making BMI screening one of the most important public health tools. As Dr. Margaret Chan, former WHO Director-General, stated: "Obesity has become a major global health challenge — early detection through BMI screening enables timely intervention." This free tool also calculates BMR, TDEE, and ideal weight range. All calculations run 100% in your browser.
BMI Categories — WHO Classification (Adults 20+)
The World Health Organization defines BMI categories for adults. Indian and Asian populations may use adjusted thresholds due to different body composition.
| BMI Range | Category | Health Risk | Note |
|---|---|---|---|
| Below 18.5 | Underweight | Moderate | May indicate malnutrition or underlying condition |
| 18.5 – 24.9 | Normal / Healthy | Low | Ideal range for most adults |
| 25.0 – 29.9 | Overweight | Increased | Lifestyle changes recommended |
| 30.0 – 34.9 | Obese Class I | High | Medical consultation recommended |
| 35.0 – 39.9 | Obese Class II | Very High | Significant health risks |
| 40.0 + | Obese Class III (Severe) | Extremely High | Urgent medical attention advised |
For Indian/Asian populations: The Ministry of Health & Family Welfare, Government of India recommends adjusted thresholds — Overweight at BMI ≥ 23 and Obese at BMI ≥ 25.
Frequently Asked Questions
What is BMI and what does it measure?
Body Mass Index (BMI) is a numerical value calculated from your weight and height. It is a screening tool used to categorise adults into weight ranges — underweight, normal weight, overweight, and obese. BMI does not measure body fat directly, but it correlates well with body fat for most people and is used worldwide by doctors, nutritionists, and public health agencies including the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC).
How is BMI calculated?
The BMI formula depends on the unit system:
Metric: BMI = weight (kg) ÷ [height (m)]²
Imperial: BMI = 703 × weight (lb) ÷ [height (in)]²
For example, a person weighing 70 kg and 1.75 m tall has a BMI of 70 ÷ (1.75 × 1.75) = 22.9, which falls in the normal range.
What is a healthy BMI range?
According to the World Health Organization, a healthy BMI for adults (20 years and older) is between 18.5 and 24.9. Below 18.5 is classified as underweight, 25.0–29.9 as overweight, and 30.0 or above as obese. For Indian and other South Asian populations, the Ministry of Health & Family Welfare recommends adjusted thresholds: overweight at BMI ≥ 23 and obese at BMI ≥ 25.
What is BMR (Basal Metabolic Rate)?
Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions at complete rest — breathing, circulating blood, regulating temperature, and cell production. BMR typically accounts for 60–75% of total daily calorie expenditure. We calculate BMR using the Mifflin-St Jeor equation, which is considered the most accurate for most adults. BMR requires your age, gender, weight, and height.
What is TDEE and how is it different from BMR?
Total Daily Energy Expenditure (TDEE) is the total number of calories you burn in a day, including BMR, physical activity, and the thermic effect of food. TDEE = BMR × Activity Factor. Your TDEE is the number of calories you need to maintain your current weight. To lose weight, eat 300–500 calories below TDEE; to gain, eat 300–500 above it. TDEE requires an activity-level input.
What is a healthy weight for my height?
Healthy weight is typically defined as the weight range that keeps your BMI between 18.5 and 24.9. For example, for a height of 175 cm, the healthy weight range is approximately 56.7 kg to 76.3 kg. Our tool displays your personalised ideal weight range in both metric and imperial units based on WHO guidelines.
Is BMI accurate for athletes and bodybuilders?
No — BMI has limitations. It does not distinguish between muscle and fat. Athletes and bodybuilders with high muscle mass may register as "overweight" or "obese" on the BMI scale despite having very low body fat. Similarly, older adults with low muscle mass may have a normal BMI but high body fat. For a fuller picture, combine BMI with waist circumference, body fat percentage, and other health metrics.
Is BMI different for men, women, and children?
For adults (20+), BMI categories are the same for men and women. For children and teenagers (2–19 years), BMI is calculated the same way but interpreted using age- and sex-specific percentile charts from the CDC or WHO. A child at the 85th–94th percentile is considered overweight; at or above the 95th percentile is obese. This tool is designed for adults.
How accurate is BMI for Indian and South Asian populations?
South Asians tend to develop health complications at lower BMI values than Caucasian populations. Studies show Indians have higher body fat at the same BMI due to genetic and lifestyle factors. The Indian Ministry of Health recommends using BMI ≥ 23 as overweight and BMI ≥ 25 as obese for Indian populations. Our tool shows the standard WHO categories — consult your doctor for personalised interpretation.
What are the health risks of high BMI?
Elevated BMI is associated with increased risk of:
- Type 2 diabetes
- Cardiovascular disease and hypertension
- Stroke
- Certain cancers (breast, colon, kidney, liver)
- Osteoarthritis and joint problems
- Sleep apnea and respiratory issues
- Gallbladder disease
- Mental health challenges (depression, low self-esteem)
According to the WHO, overweight and obesity are the fifth leading cause of death globally.
How can I lower my BMI safely?
Sustainable BMI reduction combines:
- Nutrition: Whole foods, vegetables, lean protein, portion control, minimal processed sugar
- Exercise: 150+ minutes of moderate cardio weekly + 2 days of strength training
- Sleep: 7–9 hours per night (poor sleep increases hunger hormones)
- Stress management: Meditation, yoga, adequate rest
- Consistency: Aim for 0.5–1 kg loss per week — crash diets rarely work long-term
Always consult a doctor or registered dietitian before starting any weight-loss program.
Is my data safe with this BMI calculator?
Absolutely. All calculations run 100% in your browser using JavaScript. No height, weight, age, or gender data is transmitted to any server, stored in a database, or shared with third parties. You can even use the tool offline after loading the page once.
Is this BMI calculator free?
Yes — completely free, no signup, no watermark, no limits. Brought to you by Endeavour Marketing, a digital marketing agency in Pune, India.
What other free tools does Endeavour Marketing offer?
Explore our growing library of free utility and marketing tools: Percentage Calculator (12-in-1), Age Calculator with Birthday Countdown, Meta Tag & SERP Preview Generator, Schema Markup (JSON-LD) Generator, UTM Campaign Link Builder, Email Signature Generator, QR Code Generator with Tracking, and many more.