YOURSMARTCALCULATOR

BMR Calculator

Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE). Understand how many calories your body needs at rest and with different activity levels.

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How could this calculator be better?

We're always looking to improve our tools. Here are some ideas we're considering:

  • Add more BMR calculation formulas (Katch-McArdle, Cunningham)
  • Include calorie recommendations for weight loss and gain
  • Add macronutrient distribution suggestions
  • Include adjustments for specific health conditions
  • Add personalized meal planning based on calorie needs

Email us at yoursmartcalculator@gmail.com with your suggestions!

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Quick Facts

  • •BMR accounts for 60-70% of daily calorie expenditure for most people
  • •The Mifflin-St Jeor equation is considered the most accurate for most people
  • •BMR typically decreases with age due to loss of muscle mass
  • •Building muscle can increase your BMR

Understanding BMR and TDEE

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body needs to maintain basic physiological functions while at complete rest. These functions include breathing, circulation, cell production, nutrient processing, and maintaining body temperature.

Your BMR represents the minimum amount of energy needed to keep your body functioning. It doesn't include the calories needed for daily activities, exercise, or digesting food.

BMR is influenced by several factors, including age, gender, weight, height, body composition, genetics, and hormonal factors. People with more muscle mass typically have a higher BMR because muscle tissue requires more energy to maintain than fat tissue.

What is TDEE?

Total Daily Energy Expenditure (TDEE) is the total number of calories you burn in a day, including your BMR and all activities. TDEE consists of:

  • BMR: Your basal metabolic rate (60-70% of TDEE for most people)
  • TEF: Thermic effect of food (10% of TDEE) - calories burned digesting food
  • NEAT: Non-exercise activity thermogenesis - calories burned through daily movements like walking, standing, fidgeting
  • EAT: Exercise activity thermogenesis - calories burned during intentional exercise

Your TDEE varies based on your activity level. Someone who exercises regularly will have a higher TDEE than someone who is sedentary, even if they have the same BMR.

BMR Calculation Methods

This calculator offers two common methods for calculating BMR:

  • Mifflin-St Jeor Equation: Developed in 1990, this is considered the most accurate formula for most people. It accounts for weight, height, age, and gender.
  • Harris-Benedict Equation: Originally developed in 1919 and revised in 1984, this was the standard formula for many years. It tends to overestimate BMR slightly compared to the Mifflin-St Jeor equation.

Frequently Asked Questions

Why is my BMR important to know?

Knowing your BMR helps you understand your body's baseline calorie needs. This is essential for effective weight management, as it forms the foundation for calculating your total daily calorie requirements. It also helps you make informed decisions about nutrition and exercise.

Can I increase my BMR?

Yes, you can increase your BMR by building muscle mass through strength training. Since muscle tissue requires more energy to maintain than fat tissue, having more muscle increases your BMR. Other factors that can temporarily increase metabolic rate include high-intensity exercise, certain foods (like protein and spicy foods), and staying properly hydrated.

Which BMR formula is most accurate for me?

The Mifflin-St Jeor equation is generally considered the most accurate for most people. However, if you're an athlete or have a very muscular build, the Harris-Benedict equation might be more suitable. For the most accurate measurement of your metabolic rate, consider professional testing methods like indirect calorimetry.

Should I eat fewer calories than my BMR to lose weight?

No, you should not consume fewer calories than your BMR for extended periods. Your BMR represents the minimum energy your body needs for basic functions. Consistently eating below your BMR can lead to metabolic slowdown, muscle loss, nutritional deficiencies, and other health problems. For healthy weight loss, aim for a moderate calorie deficit based on your TDEE, not your BMR.

Why does BMR decrease with age?

BMR typically decreases with age due to several factors: loss of muscle mass (sarcopenia), hormonal changes, and decreased cellular activity. On average, BMR decreases by about 1-2% per decade after age 20. Regular strength training and maintaining muscle mass can help mitigate this decline.