🔥 BMR Calculator

What is the BMR Calculator?

Basal Metabolic Rate (BMR) is the number of calories your body needs to maintain basic physiological functions — breathing, circulation, cell production — while at complete rest. This calculator computes your BMR using both the Mifflin-St Jeor and Harris-Benedict formulas from your age, sex, height, and weight, then estimates your Total Daily Energy Expenditure (TDEE) at sedentary and moderate activity levels.

How to Use It

Enter your age, sex, height in centimeters, and weight in kilograms, then click "Calculate." You'll get your BMR under two formulas plus two TDEE estimates — sedentary and moderately active — showing roughly how many calories you burn per day depending on activity level.

When to Use It

Use it before setting a calorie target for weight loss, maintenance, or muscle gain, since BMR is the baseline your daily calorie needs build on. It's also useful for understanding why very low-calorie diets can backfire — dropping below your BMR for extended periods can slow metabolism and cause muscle loss.

Who Benefits

Dieters and bodybuilders planning a calorie deficit or surplus, athletes tracking energy needs during training cycles, and anyone curious about their baseline metabolic rate before adjusting diet or exercise habits.