BMI Calculator
Calculate your Body Mass Index (BMI) to determine if you're underweight, normal weight, overweight, or obese. Supports both metric and imperial units.
BMI Calculator
About This Calculator
Body Mass Index (BMI) is a simple calculation using a person's height and weight. The BMI is a convenient rule of thumb used to broadly categorize a person as underweight, normal weight, overweight, or obese based on tissue mass (muscle, fat, and bone) and height.
Our BMI calculator supports both metric (kg/cm) and imperial (lbs/inches) units, making it accessible for users worldwide. The results include your BMI value, weight category, and reference ranges for all categories.
BMI Categories:
- Underweight: BMI less than 18.5
- Normal weight: BMI 18.5-24.9
- Overweight: BMI 25-29.9
- Obese: BMI 30 or higher
Note: BMI is a screening tool and is not diagnostic. Consult with a healthcare professional for proper medical assessment.
Frequently Asked Questions
What is BMI and how is it calculated?
BMI (Body Mass Index) is calculated by dividing your weight in kilograms by your height in meters squared (BMI = kg/m²). It's a simple screening tool to categorize weight status. For example, if you weigh 70 kg and are 1.75 m tall: BMI = 70 ÷ (1.75 × 1.75) = 22.9, which falls in the normal weight category. Our calculator supports both metric (kg/cm) and imperial (lbs/inches) units.
What is a healthy BMI range?
According to WHO standards: Underweight: BMI less than 18.5, Normal weight: BMI 18.5-24.9, Overweight: BMI 25-29.9, Obese: BMI 30 or higher. For Indians and South Asians, the thresholds are lower due to higher health risks at lower BMIs: Normal: 18.0-22.9, Overweight: 23-24.9, Obese: 25 or higher. This is because Asians tend to have higher body fat percentage at lower BMIs.
Is BMI accurate for everyone?
BMI is not accurate for everyone. It doesn't distinguish between muscle and fat, so athletes with high muscle mass may have "overweight" BMI despite being healthy. It also doesn't account for age, gender, bone density, or fat distribution. BMI may underestimate body fat in elderly and overestimate it in very muscular individuals. Use BMI as a general guideline, not a definitive health measure.
What is a good BMI for my age?
BMI categories apply to adults 18-65 years. For adults over 65, slightly higher BMI (23-27) may be protective against malnutrition and frailty. For children and teens (2-18 years), BMI is interpreted using age and gender-specific percentile charts, not adult categories. Consult a pediatrician for children's weight assessments.
How to lower my BMI?
Lower BMI by creating a caloric deficit: 1) Reduce calorie intake by 300-500 per day, 2) Eat more protein and fiber to stay full, 3) Exercise 150+ minutes weekly (cardio + strength training), 4) Get 7-9 hours sleep, 5) Manage stress (cortisol increases weight), 6) Stay hydrated. Aim to lose 0.5-1 kg per week for sustainable results. Avoid crash diets that promise rapid weight loss.
Why do men and women have different healthy BMI ranges?
Women naturally have higher body fat percentage than men (essential fat for reproductive health). Healthy body fat ranges: Men 10-20%, Women 20-30%. However, the standard BMI categories are the same for both sexes. The difference is accounted for in body fat percentage charts, not BMI charts. Both should aim for the same BMI range of 18.5-24.9.
Can you be overweight but still healthy?
Yes, some people with BMI 25-27 can be metabolically healthy if they maintain good blood pressure, blood sugar, and cholesterol levels. This is sometimes called "fit but fat." However, as BMI increases above 27-28, health risks generally increase regardless of metabolic markers. Waist circumference and body fat percentage provide additional health insights.
What waist size should I aim for?
Waist circumference is often a better health indicator than BMI. For Indians, men should aim for waist less than 90 cm (36 inches), women less than 80 cm (32 inches). Higher waist sizes indicate more visceral (belly) fat, which is linked to diabetes and heart disease. Even with normal BMI, a large waist can indicate health risks. Measure at the navel level while breathing normally.
How often should I check my BMI?
Check BMI monthly if you're actively trying to lose or gain weight. For weight maintenance, check every 3-6 months. Don't obsess over daily fluctuations - focus on trends over months. Measure at the same time of day, preferably morning after using the bathroom, for consistency. Remember that BMI is just one indicator - also track energy levels, fitness, and how your clothes fit.
What are BMI limitations for Indians?
Standard BMI thresholds were developed using Western populations. Research shows Indians and South Asians develop diabetes and heart disease at lower BMIs than Caucasians. The Indian Health Ministry recommends lower cut-offs: Overweight 23 or higher, Obese 25 or higher. This is because South Asians tend to have more body fat and less muscle at the same BMI compared to other ethnic groups.