BMR Calculator

Discover the minimum amount of calories your body burns per day at rest. Essential for those looking to lose, maintain, or gain weight.

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How does this tool work?

  • Enter gender, age, height, weight: Basic biometric data.
  • Select activity level: Choose from sedentary to extra active to get Total Daily Energy Expenditure (TDEE).
  • Calculate BMR and TDEE: The tool computes Basal Metabolic Rate and multiplies by activity factor.
  • Use for goals: Adjust calories for weight loss (deficit) or gain (surplus).
  • Revisit periodically: Update as your weight or activity changes.

What is Basal Metabolic Rate (BMR)?

The Basal Metabolic Rate (BMR) represents the total calories your body burns just to keep vital functions running, such as heartbeat, breathing, body temperature regulation, and cell renewal.

Understanding this number is the first step for any nutritional planning. If you consume more calories than your BMR plus your physical activity level, you gain weight; if you consume less, you lose weight.

How is the calculation performed?

Our tool uses the Mifflin-St Jeor formula, currently considered the most accurate by the scientific community. The calculation differentiates between men and women due to average muscle mass composition:

  • Men: (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5
  • Women: (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161

Important Note

This calculation provides an estimate. Factors such as body fat percentage, genetics, and hormonal issues can change actual expenditure. Always consult a nutritionist. Also calculate your BMI.

Frequently Asked Questions

BMR (Basal Metabolic Rate) is the energy your body needs at complete rest. TDEE (Total Daily Energy Expenditure) is the sum of your BMR plus the calories burned through physical activity and digestion. To maintain your current weight, you should look at your TDEE, not just your BMR.

As we age, our body composition naturally changes. We tend to lose lean muscle mass and increase fat percentage, which slows down the metabolism. This is why age is a subtracting factor in the Mifflin-St Jeor formula; the older we get, the fewer calories our bodies burn at rest.

It is generally not recommended to consume fewer calories than your BMR without medical supervision. Since BMR represents the energy needed for vital organ functions, extreme deficits can lead to muscle loss, nutrient deficiencies, and a "starvation mode" that actually makes long-term weight loss harder by slowing your metabolism further.

The Mifflin-St Jeor formula is widely considered the most accurate for the general population. However, it does not account for body composition (percentage of muscle vs. fat). Athletes with high muscle mass may find their BMR underestimated, while individuals with high body fat may find it slightly overestimated.

The most effective way to increase your BMR is by building muscle mass. Muscle tissue is metabolically active and burns more energy than fat tissue, even when you are sleeping. Strength training and adequate protein intake are key to speeding up your metabolism over time.

On average, men tend to have a higher percentage of lean muscle mass and lower body fat than women. Because muscle requires more energy to maintain than fat, men typically burn more calories at rest, which is reflected in the mathematical constants used in the calculation.

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