Calculate your Basal Metabolic Rate, the calories your body burns at rest, using the Mifflin-St Jeor and Harris-Benedict formulas.
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Fill in your physical attributes to predict resting energy expenditure baselines.
This is the minimum energy required to keep your body alive at rest with no physical movements.
Basal Metabolic Rate (BMR) represents the minimum number of calories your body needs to function at rest (e.g. breathing, circulation, cell production, temperature regulation). BMR...
Understanding basal calories and the metabolic mechanisms driving daily energy burn.
BMR represents the baseline amount of thermal energy required to keep your body functional in a resting state. It accounts for about 60% to 75% of your total daily energy output.
Your organs (liver, brain, heart, kidneys) utilize the majority of resting baseline energy, even when you are asleep.
BMR is your resting metabolic rate. Total Daily Energy Expenditure (TDEE) factors in physical activity and digestive processes.
Several physiological factors regulate BMR:
For men, BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) + 5. For women, the same terms are used but 161 is subtracted instead of adding 5. This equation, published in 1990, is generally considered the more accurate default for most modern adults.
This calculator uses the 1984 Roza and Shizgal revision of the original 1918 Harris-Benedict formula: for men, BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) - (5.677 x age); for women, BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) - (4.330 x age). It tends to produce a slightly higher result than Mifflin-St Jeor for the same inputs.
For a 30-year-old man who is 178 cm tall and weighs 75 kg, Mifflin-St Jeor gives roughly 1,718 kcal/day, while the revised Harris-Benedict formula gives roughly 1,777 kcal/day for the same inputs. Both are resting-only estimates and exclude any calories burned through movement or exercise.
BMR only reflects energy needs at complete rest, so multiply it by an activity factor using the Calorie Calculator or TDEE Calculator to estimate realistic total daily calorie needs for weight maintenance, loss, or gain.
Quick answers about how this tool works.
Metabolism is the cellular chemical process of converting food intake into physical energy. BMR naturally declines with age (roughly 1-2% per decade after age 30) due to gradual muscle tissue loss. Regular strength training can help maintain muscle and preserve BMR.
Yes, BMR is the energy required to survive in a comatose state at rest. However, any physical activity—including sitting, walking, or eating—requires additional calories. Consuming fewer calories than your BMR for long periods forces the body to conserve energy, potentially slowing down weight loss and causing muscle depletion.
Basal Metabolic Rate (BMR) is the number of calories your body needs each day to perform essential life-sustaining functions such as breathing, circulation, cell production, and temperature regulation while at complete rest.
BMR is calculated using factors such as age, gender, height, and weight. This calculator uses scientifically validated equations like the Mifflin-St Jeor or Harris-Benedict formulas to estimate your daily resting energy requirements.
BMR represents the calories your body needs at complete rest, while Total Daily Energy Expenditure (TDEE) includes all calories burned through daily activities, exercise, digestion, and movement throughout the day.
Understanding your BMR helps you estimate your daily calorie needs, create effective weight loss or weight gain plans, and make informed nutrition decisions based on your body's energy requirements.
Yes. BMR serves as a starting point for determining calorie intake. By estimating your total daily calorie needs and creating a moderate calorie deficit, you can develop a sustainable weight loss strategy.
Yes. Muscle tissue requires more energy to maintain than fat tissue, so individuals with greater muscle mass generally have a higher BMR and burn more calories at rest.
Regular exercise, particularly strength training, can increase muscle mass and help raise your BMR over time. Cardiovascular exercise also supports overall calorie expenditure and metabolic health.
Plain-language explainers that sit next to this tool.
Most people confuse BMR and TDEE — and eating at your BMR instead of your TDEE is the #1 calorie calculation mistake. This guide explains the difference and tells you exactly which number to use for your goal.
TDEE is the total number of calories your body burns in a day — at rest and through activity. It is the master number behind every effective diet and fitness plan. This guide explains how TDEE is calculated and why it matters more than BMR alone.
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