BMI & Calorie Calculator
Calculate your Body Mass Index (BMI), Basal Metabolic Rate (BMR), and daily calorie needs based on your goals and activity level. Supports both metric and imperial units.
BMI Result
24.4
Normal
Daily Calories
Disclaimer
This calculator provides estimates for general informational and educational purposes only. It is not medical advice and should not replace consultation with a qualified healthcare provider. Always speak with your doctor before making changes to your diet, exercise routine, or health regimen.
How It Works
- Enter your height, weight, age, and gender.
- Select your activity level from sedentary to very active.
- The calculator uses the Mifflin-St Jeor equation for BMR estimation.
- View your BMI category, maintenance calories, and calorie targets for weight loss or gain.
Understanding BMI, BMR, and Calorie Needs
Body Mass Index (BMI) is a widely used screening measure that estimates body fat based on your height and weight. It is calculated by dividing your weight in kilograms by the square of your height in meters. While BMI does not directly measure body fat, it is correlated with more direct measures of body fat and serves as a quick and inexpensive screening tool for weight categories: underweight (below 18.5), normal weight (18.5 to 24.9), overweight (25 to 29.9), and obese (30 and above).
Basal Metabolic Rate (BMR) represents the number of calories your body needs to maintain basic life-sustaining functions like breathing, circulation, and cell production while at complete rest. Our calculator uses the Mifflin-St Jeor equation, which is considered one of the most accurate formulas for estimating BMR. Your Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor that accounts for your physical activity level.
Understanding your TDEE is key to managing your weight. To maintain your current weight, consume roughly the same number of calories as your TDEE. For gradual weight loss, a deficit of 500 calories per day below your TDEE typically results in about 0.5 kg (1 pound) of weight loss per week. For weight gain, a surplus of about 500 calories per day above your TDEE supports gradual muscle building when combined with strength training.
Tips & Best Practices
- ✓BMI is a screening tool, not a diagnostic measure. Athletes with high muscle mass may have a high BMI despite having low body fat.
- ✓For a more accurate picture of health, consider combining BMI with waist circumference measurements and body fat percentage.
- ✓When setting calorie goals, aim for gradual changes. Extreme calorie restriction can be counterproductive and unhealthy.
- ✓Adjust your activity level honestly in the calculator. Overestimating activity is a common source of inaccurate calorie estimates.
- ✓Consult a healthcare professional before making significant changes to your diet or exercise routine.
Frequently Asked Questions
How accurate is BMI?
BMI is a useful general indicator but has limitations. It does not distinguish between muscle and fat mass, so muscular individuals may be classified as overweight. It also does not account for fat distribution, age, sex, or ethnicity. It is best used as one of several health indicators rather than a definitive diagnosis.
What is the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation is a formula for estimating Basal Metabolic Rate. For men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5. For women: the same formula minus 161 instead of plus 5. It is considered more accurate than the older Harris-Benedict equation.
What do the activity levels mean?
Sedentary means little or no exercise. Lightly active is light exercise 1-3 days per week. Moderately active is moderate exercise 3-5 days per week. Very active is hard exercise 6-7 days per week. Extra active is very hard exercise plus a physical job or training twice per day.
Is BMI the same for children and adults?
No. For children and teenagers, BMI is interpreted differently using age- and sex-specific percentiles. A child's BMI is compared to other children of the same age and sex. This calculator is designed for adults aged 18 and older.