Advanced BMI & BMR Calculator

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m², where kg is a person's weight in kilograms and m² is their height in metres squared.

BMR is the total number of calories that your body needs to perform basic, life-sustaining functions. These basal functions include breathing, circulation, and cell production.

TDEE is an estimation of how many calories you burn per day when exercise is taken into account. It is calculated by multiplying your BMR by an activity multiplier.

BMI is a useful population-level screening tool, but it doesn't measure body fat directly. It doesn't account for muscle mass, bone density, or overall body composition.

The Mifflin-St Jeor equation, introduced in 1990, has been proven to be more accurate than the older Harris-Benedict equation (created in 1919) which tends to overestimate calorie needs by about 5%.

According to the World Health Organization (WHO): Under 18.5 is Underweight, 18.5 to 24.9 is Normal, 25 to 29.9 is Overweight, and 30 or greater is Obese.

If you have high muscle mass, BMI might classify you as 'Overweight' or 'Obese' because muscle is denser than fat. In such cases, measuring body fat percentage is more accurate than BMI.

To lose weight safely, you should consume fewer calories than your TDEE. A common deficit is 500 calories below your TDEE per day, which typically results in about 0.5 kg (1 lb) of weight loss per week.

Yes, as you age, your muscle mass tends to decrease and fat accounts for a greater proportion of your weight. This slows down your metabolism, which is why BMR decreases with age.