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BMR Calculator

Calculate your Basal Metabolic Rate (BMR) - the calories your body burns at rest - and your Total Daily Energy Expenditure (TDEE).

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Understanding Your BMR

What Is BMR?

Basal Metabolic Rate is the minimum calories your body needs to sustain vital functions - breathing, circulation and cell production - while at complete rest.

Mifflin–St Jeor

The most accurate widely used formula (1990). Men: 10×W + 6.25×H − 5×A + 5. Women: 10×W + 6.25×H − 5×A − 161. (W=kg, H=cm, A=age).

TDEE

Total Daily Energy Expenditure = BMR × Activity multiplier. This is the true calorie target for maintenance. Eat less to lose weight, more to gain.

BMR Questions

BMR is the calories burned at total rest. TDEE (Total Daily Energy Expenditure) adds the calories burned through all daily activity. To maintain weight, consume TDEE calories. To lose weight at ~0.5 kg/week, eat 500 kcal below TDEE.

Mifflin–St Jeor (1990) is considered more accurate for most people. Harris-Benedict (revised 1984) tends to overestimate slightly. Both are estimates; actual metabolic rate varies by body composition - use them as starting points.

Muscle mass naturally decreases with age (sarcopenia), reducing BMR by roughly 1–2% per decade after 30. Staying active and maintaining muscle through strength training partially offsets this decline.

BMR Calculator - Basal Metabolic Rate Explained

Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest to sustain essential life functions - breathing, circulation, cell repair, hormone production, and temperature regulation. It represents the floor of your daily energy expenditure and typically accounts for 60-75% of total daily energy use. BMR was first systematically studied by Max Rubner in 1883 and later quantified through the foundational 1919 Harris-Benedict equations, which were revised and updated by Mifflin and St Jeor in 1990.

BMR Formulas - Mifflin-St Jeor vs Harris-Benedict

The Mifflin-St Jeor equation, published in 1990 in the American Journal of Clinical Nutrition, is now considered the most accurate predictor of BMR for most adults, with a mean error of approximately 10%. The older Harris-Benedict formula (revised 1984) tends to overestimate BMR by 5% on average. Both formulas use weight (kg), height (cm), age (years), and sex as inputs. Multiplying BMR by an activity factor (sedentary 1.2, lightly active 1.375, moderately active 1.55, very active 1.725) gives TDEE - Total Daily Energy Expenditure.

Calorie Awareness in India

India faces a dual nutritional burden: the National Family Health Survey (NFHS-5, 2019-21) shows 22.9% of adults are overweight or obese, while 32.1% of women remain undernourished. Dietitians registered with the Indian Dietetic Association (IDA) use BMR calculations as the starting point for therapeutic diet plans. Fitness apps popular in India like HealthifyMe and GOQii incorporate BMR-based calorie targets. Understanding your BMR helps set realistic calorie goals for weight management without the risk of metabolic adaptation from extreme restriction.

Frequently Asked Questions

BMR is the number of calories your body burns at complete rest to maintain basic life functions - breathing, circulation, cell production and organ function. It represents the minimum calories needed to stay alive and accounts for about 60–75% of your total daily calorie burn. Knowing your BMR helps you understand your body's baseline energy requirement before activity.

Harris-Benedict (1919, revised 1984) was the standard formula for decades. Mifflin-St Jeor (1990) is now considered more accurate and is recommended by the Academy of Nutrition and Dietetics - it gives results about 5% lower than Harris-Benedict. For most people the difference is 50–150 calories per day. Our calculator uses both formulas so you can compare.

TDEE (Total Daily Energy Expenditure) is your total calorie burn per day including all activity. Sedentary = BMR × 1.2; Lightly active = BMR × 1.375; Moderately active = BMR × 1.55; Very active = BMR × 1.725; Extra active = BMR × 1.9. TDEE is the number of calories you need daily to maintain your current weight.

Yes - BMR decreases with age due to muscle loss at roughly 1–2% per decade after 30. BMR also decreases when you lose weight, since a lighter body burns fewer calories at rest. Strength training helps preserve muscle mass, which maintains a higher BMR during weight loss and aging.