Maintaining a healthy weight is one of the most important steps you can take for long-term health. But how do you know if your current weight is healthy for your height?

This free BMI Calculator gives you your Body Mass Index instantly along with your healthy weight range, resting metabolism (BMR), personalised health tips and the ability to compare your BMI with up to 3 family members or friends. Supports both Metric (kg, cm) and Imperial (lbs, ft/in) units

How to Use the BMI Calculator

Step 1 — Select your unit system Choose Metric (kg and cm) or Imperial (lbs and ft/in) using the toggle at the top.

Step 2 — Enter your weight Use the slider or type your weight directly. The slider ranges from 30 kg to 200 kg (or 66 lbs to 440 lbs in imperial).

Step 3 — Enter your height For metric, enter height in centimeters. For imperial, enter feet and inches separately.

Step 4 — Enter age and biological sex Age and sex are used to calculate your Basal Metabolic Rate (BMR) — the calories your body burns at rest. This helps provide more personalized recommendations.

Step 5 — Read your results See your BMI number, category, position on the scale, healthy weight range and personalized tips.

Step 6 — Compare with others (optional) Toggle the Compare BMI with Others switch and enter weight and height for up to 3 more people to compare BMI side by side.

What is BMI and What Does It Mean?

BMI stands for Body Mass Index. It is a simple numerical value calculated from a person's height and weight that provides an indication of whether a person has a healthy body weight relative to their height.

BMI was developed in the 1830s by Belgian mathematician Adolphe Quetelet as a population-level measure. While it has limitations as an individual diagnostic tool, it remains the most widely used screening measure for weight-related health risks worldwide.

BMI categories (WHO and Indian standards):

BMI Range Category Health Risk
Below 18.5 Underweight Moderate
18.5 to 24.9 Normal Weight Low
25.0 to 29.9 Overweight Moderate
30.0 to 34.9 Obese Class I High
35.0 and above Obese Class II+ Very High

Note for Indian context: Several studies suggest that Indians and South Asians tend to carry more body fat at lower BMI values compared to Western populations. Some Indian health guidelines suggest the overweight threshold for Indians should be 23 rather than 25, and obese threshold at 25 rather than 30. Always discuss your specific situation with a doctor.

How BMI is Calculated

Metric formula:

BMI = Weight (kg) / Height (m)²

Example: Weight = 70 kg Height = 170 cm = 1.70 m

BMI = 70 / (1.70)² = 70 / 2.89 = 24.2

Category: Normal Weight ✅

Imperial formula:

BMI = [Weight (lbs) / Height (inches)²] × 703

Example: Weight = 154 lbs Height = 5 ft 7 in = 67 inches

BMI = [154 / (67)²] × 703 = [154 / 4489] × 703 = 24.1

Category: Normal Weight ✅

Understanding Basal Metabolic Rate (BMR)

BMR is the number of calories your body needs to perform basic life-sustaining functions at complete rest — breathing, circulation, cell production and temperature regulation.

Mifflin-St Jeor Formula (most accurate):

For males:

BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5

For females:

BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

Daily calorie needs based on activity level:

Activity Level Multiplier Example (BMR = 1,600)
Sedentary (desk job, no exercise) × 1.2 1,920 kcal
Lightly active (1-3 days/week) × 1.375 2,200 kcal
Moderately active (3-5 days/week) × 1.55 2,480 kcal
Very active (6-7 days/week) × 1.725 2,760 kcal
Extra active (physical job + training) × 1.9 3,040 kcal

What is a Healthy Weight Range for Your Height?

The healthy weight range is calculated by finding the weight that corresponds to a BMI between 18.5 and 24.9 for your specific height.

Quick reference for common heights (Indian adults):

Height Healthy Weight Range
155 cm (5'1") 44.5 kg — 59.9 kg
160 cm (5'3") 47.4 kg — 63.7 kg
165 cm (5'5") 50.4 kg — 67.7 kg
170 cm (5'7") 53.5 kg — 71.9 kg
175 cm (5'9") 56.7 kg — 76.3 kg
180 cm (5'11") 59.9 kg — 80.6 kg

Our calculator shows your personal healthy weight range based on your exact height.

Frequently Asked Questions

Q1. What is a healthy BMI for Indians? While WHO uses 18.5 to 24.9 as the normal BMI range globally, studies show that Indians and South Asians face higher health risks at lower BMI values. Several Indian health organizations recommend the healthy range for Indians as 18.5 to 22.9, with overweight starting at 23 and obesity at 25. Our calculator uses the international WHO standards but this context is important.

Q2. Is BMI accurate for muscular people? BMI does not distinguish between muscle and fat. A very muscular person like an athlete or bodybuilder may have a high BMI but very low body fat percentage — giving a misleading result. In such cases, a body fat percentage measurement using DEXA scan or skinfold calipers is more accurate than BMI.

Q3. How do I lose weight to reach a healthy BMI? A safe and sustainable rate of weight loss is 0.5 kg to 1 kg per week. This requires a calorie deficit of approximately 500 to 1,000 calories per day through a combination of reduced food intake and increased physical activity. Crash diets that promise rapid weight loss are not sustainable and often lead to muscle loss and nutrient deficiencies.

Q4. What is the ideal weight for a 5 foot 4 inch woman? For a height of 5 feet 4 inches (162.5 cm), the healthy weight range is approximately 48.7 kg to 65.5 kg based on a BMI of 18.5 to 24.9. However, as noted above, Indian women may want to target the lower end of this range (48 to 59 kg) based on Indian-specific guidelines.

Q5. What is the BMI of a 70 kg person who is 170 cm tall? BMI = 70 / (1.70)² = 70 / 2.89 = 24.2. This falls in the Normal Weight category (18.5 to 24.9). The person is in the healthy range.

Q6. Does BMI change with age? BMI itself is calculated the same way regardless of age. However, the health implications of a given BMI value differ slightly with age. For children and teenagers, BMI is interpreted using age and sex-specific percentile charts rather than fixed cutoffs. For older adults (65+), a slightly higher BMI of 23 to 27 may actually be associated with better health outcomes according to some research.

Q7. What are the health risks of being overweight? A BMI above 25 is associated with increased risk of type 2 diabetes, high blood pressure, cardiovascular disease, certain cancers (colon, breast, endometrial), sleep apnea, joint problems particularly knees and hips, and fatty liver disease. Even a 5% to 10% reduction in body weight significantly reduces these risks.

Q8. What are the health risks of being underweight? A BMI below 18.5 is associated with nutrient deficiencies, anemia, weakened immune system, bone density loss and osteoporosis, fertility issues in women, and delayed healing and recovery from illness. Being underweight is a serious health concern that requires proper dietary intervention.

Q9. How accurate is the BMI calculator for children? BMI for children aged 2 to 18 is calculated the same way but interpreted differently using age and sex-specific percentile charts developed by WHO and CDC. A BMI in the 85th to 95th percentile is considered overweight for children, and above 95th percentile is obese. Adult BMI categories should not be used for children. Our calculator is designed for adults aged 18 and above.

Q10. What should I do if my BMI indicates I am obese? A BMI above 30 is a health concern that warrants medical attention. We strongly recommend consulting a physician who can assess your overall health comprehensively — beyond just BMI. A doctor may recommend dietary changes, an exercise program, and in some cases medication or bariatric surgery for severe obesity. Do not attempt extreme diets without medical supervision.