Calculate your Basal Metabolic Rate - the number of calories your body burns at complete rest. Compare results from multiple scientific formulas.
If provided, the Katch-McArdle formula becomes available for more accurate results
BiteKit helps you track the rest. Log your meals with voice or text and let AI calculate the nutrition for you automatically.
BMR (Basal Metabolic Rate) is the number of calories your body needs to perform its most basic life-sustaining functions. These include breathing, circulation, cell production, nutrient processing, protein synthesis, and ion transport.
Think of BMR as the energy cost of simply being alive - even while sleeping, your body is constantly working. BMR typically accounts for about 60-75% of your total daily calorie expenditure, making it the largest component of your metabolism.
Understanding the difference between BMR and TDEE is crucial for effective nutrition planning:
Calories burned at complete rest. This is the absolute minimum energy your body needs to survive, measured in a completely rested, fasted state.
60-75% of total calories
Your BMR plus all additional calories burned through daily activities, exercise, and the thermic effect of food. This is what you actually burn each day.
TDEE = BMR x Activity Factor
Key insight: You should never eat below your BMR for extended periods, as this can slow your metabolism and be harmful to your health. Use TDEE for setting calorie goals.
Several factors influence your Basal Metabolic Rate. Understanding these can help you optimize your metabolism:
Muscle tissue burns more calories than fat tissue, even at rest. More muscle = higher BMR. This is why strength training is valuable for metabolism.
BMR decreases by about 1-2% per decade after age 20, primarily due to muscle loss and hormonal changes. Staying active helps minimize this decline.
Men typically have higher BMRs than women due to greater muscle mass and different hormonal profiles. This is reflected in the calculation formulas.
Larger bodies require more energy to maintain. Both height and weight contribute to BMR - taller and heavier individuals have higher metabolic rates.
Thyroid hormones significantly impact metabolism. Genetics also play a role, with some people naturally having faster or slower metabolisms.
While some factors are out of your control, there are proven ways to boost your metabolic rate:
Strength training builds lean muscle mass, which burns 6-10 calories per pound daily vs. 2-3 for fat. Prioritize resistance exercises 2-4 times per week.
Protein has a higher thermic effect - your body burns 20-30% of protein calories during digestion vs. 5-10% for carbs. Aim for 0.7-1g per pound of body weight.
NEAT (Non-Exercise Activity Thermogenesis) - walking, standing, fidgeting - can burn 300-500 extra calories daily. Take breaks from sitting every hour.
Poor sleep disrupts hunger hormones and can lower BMR. Aim for 7-9 hours of quality sleep. Sleep deprivation can reduce metabolic rate by 2-8%.
Severely restricting calories can lower your BMR by 20-30% as your body enters "starvation mode." This metabolic adaptation can persist even after you resume normal eating. A moderate deficit of 500 calories is safer and more sustainable.
Our calculator uses three scientifically validated formulas. Here's how each one works:
Men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) + 5
Women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) - 161
Studies show this is the most accurate formula for most modern populations. Recommended by the American Dietetic Association.
Men: BMR = 88.362 + (13.397 x weight) + (4.799 x height) - (5.677 x age)
Women: BMR = 447.593 + (9.247 x weight) + (3.098 x height) - (4.330 x age)
The original BMR formula, widely used for over a century. May overestimate BMR for modern populations by 5-15%.
BMR: 370 + (21.6 x lean body mass in kg)
Uses lean body mass instead of total weight, making it more accurate for athletes and those with unusual body compositions. Requires knowing your body fat percentage.
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest to maintain basic life functions like breathing, circulation, and cell production. It represents the minimum energy your body needs to survive.
BMR is the calories burned at complete rest, while TDEE includes BMR plus all calories burned through daily activities and exercise. Your TDEE equals your BMR multiplied by an activity factor, and is always higher than your BMR.
The Mifflin-St Jeor equation is considered most accurate for most people. If you know your body fat percentage, the Katch-McArdle formula may be more accurate as it accounts for lean body mass.
Build muscle through strength training, eat adequate protein, stay active throughout the day, get enough sleep, and avoid extreme calorie restriction. Muscle burns more calories than fat, even at rest.
Knowing your BMR helps you understand your baseline calorie needs and is essential for creating effective nutrition plans. Never eat below your BMR for extended periods - use it as a minimum threshold and calculate TDEE for actual calorie goals.
Yes, BMR decreases by about 1-2% per decade after age 20, primarily due to muscle loss and hormonal changes. Regular exercise and strength training can help minimize this decline.
Now that you know your BMR, track your nutrition effortlessly with BiteKit. Log meals with your voice or text and let AI handle the calculations.
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