BMR Calculator

Calculate your Basal Metabolic Rate (BMR) using proven formulas like Mifflin-St Jeor and Harris-Benedict. Get detailed analysis of daily calorie needs based on your activity level and health goals.

BMR Calculator

ages 15 - 80

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Enter your details to calculate your BMR.

Understanding BMR (Basal Metabolic Rate)

Basal Metabolic Rate (BMR) represents the number of calories your body burns at rest to maintain vital functions like breathing, circulation, cell production, and brain function. It's the minimum energy requirement your body needs to survive in a fasting state at room temperature.

What Affects Your BMR?

Age

BMR decreases by about 2% per decade after age 20 due to muscle mass loss and slower cellular processes.

Gender

Men typically have higher BMRs than women due to greater muscle mass and larger body size.

Body Composition

Muscle tissue burns more calories than fat tissue, so higher muscle mass increases BMR.

Body Size

Larger bodies require more energy to maintain basic functions, resulting in higher BMRs.

BMR vs. TDEE

BMR is different from Total Daily Energy Expenditure (TDEE). While BMR represents calories burned at rest, TDEE includes all calories burned throughout the day, including physical activity, exercise, and the thermic effect of food.

  • BMR (60-75%): Energy for basic bodily functions at rest
  • Physical Activity (15-25%): Exercise and planned physical activities
  • Thermic Effect of Food (8-10%): Energy to digest, absorb, and process food
  • Non-Exercise Activity (5-15%): Fidgeting, maintaining posture, other spontaneous activities
Important Note: BMR calculators provide estimates based on population averages. Individual BMR can vary by ±10-15% due to genetics, hormones, and other factors not captured in standard formulas.

Metabolism and Metabolic Health Guide

Your metabolism is the sum of all chemical processes that occur in your body to maintain life. Understanding how metabolism works can help you make informed decisions about nutrition, exercise, and lifestyle choices to optimize your energy expenditure and health.

Factors That Boost Metabolism

Strength Training

Building muscle mass increases BMR since muscle tissue burns more calories at rest than fat tissue.

High-Intensity Exercise

HIIT workouts create an 'afterburn effect' where your body continues burning calories hours after exercise.

Protein Intake

Protein has a higher thermic effect than carbs or fats, burning 20-30% of calories consumed during digestion.

Cold Exposure

Cold temperatures force your body to burn more calories to maintain core temperature.

Metabolism Myths Debunked

  • Myth: Small meals boost metabolism: Research shows meal frequency has minimal impact on total daily energy expenditure
  • Myth: Certain foods have 'negative calories': While some foods require energy to digest, none actually result in negative calories
  • Myth: Metabolism slows dramatically with age: BMR decreases gradually (~2% per decade), but staying active can maintain metabolic health
  • Myth: Thin people always have fast metabolisms: Body size and composition matter more than weight alone for metabolic rate

Optimizing Your Metabolic Health

Focus on sustainable lifestyle changes rather than quick fixes. Regular exercise, adequate protein intake, sufficient sleep, and stress management are the most effective ways to maintain a healthy metabolism throughout life.

Pro Tip: The most significant factor you can control for metabolic health is maintaining muscle mass through regular strength training and adequate protein intake.

Frequently Asked Questions