nutrition
Bmr calculator
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and organs functioning. It accounts for roughly 60–75% of total daily calorie expenditure for most people.
How to use this calculator
- Enter your weight, height, age, and biological sex.
- Optionally enter your body fat percentage to unlock the Katch-McArdle formula.
- Click Calculate BMR to compare results across all formulas.
- Use the Mifflin-St Jeor result as the default — it is the most validated formula for the general population.
The formulas
Mifflin-St Jeor (recommended)
Male: 10 × kg + 6.25 × cm − 5 × age + 5
Female: 10 × kg + 6.25 × cm − 5 × age − 161
Harris-Benedict (1984 revised)
Male: 13.397 × kg + 4.799 × cm − 5.677 × age + 88.362
Female: 9.247 × kg + 3.098 × cm − 4.330 × age + 447.593
Katch-McArdle (requires body fat %)
BMR = 370 + 21.6 × lean body mass (kg)
How to interpret your result
The three formulas typically differ by 50–150 kcal/day. If you know your body fat percentage, Katch-McArdle tends to be the most accurate because it accounts for lean mass directly. Multiply your BMR by your activity factor to get your TDEE.
Related tools
- TDEE Calculator — multiply BMR by an activity factor
- Macro Calculator — set protein, fat, and carb targets from your TDEE
Read more
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest — just to keep your heart beating, lungs breathing, and organs functioning. It accounts for roughly 60–75% of total daily calorie expenditure for most people.
How to use this calculator
- Enter your weight, height, age, and biological sex.
- Optionally enter your body fat percentage to unlock the Katch-McArdle formula.
- Click Calculate BMR to compare results across all formulas.
- Use the Mifflin-St Jeor result as the default — it is the most validated formula for the general population.
The formulas
Mifflin-St Jeor (recommended)
Male: 10 × kg + 6.25 × cm − 5 × age + 5
Female: 10 × kg + 6.25 × cm − 5 × age − 161
Harris-Benedict (1984 revised)
Male: 13.397 × kg + 4.799 × cm − 5.677 × age + 88.362
Female: 9.247 × kg + 3.098 × cm − 4.330 × age + 447.593
Katch-McArdle (requires body fat %)
BMR = 370 + 21.6 × lean body mass (kg)
How to interpret your result
The three formulas typically differ by 50–150 kcal/day. If you know your body fat percentage, Katch-McArdle tends to be the most accurate because it accounts for lean mass directly. Multiply your BMR by your activity factor to get your TDEE.
Related tools
- TDEE Calculator — multiply BMR by an activity factor
- Macro Calculator — set protein, fat, and carb targets from your TDEE
Frequently asked questions
What is BMR?
Basal Metabolic Rate is the calories your body burns at complete rest to run essential functions — breathing, circulation, and cell production. It accounts for about 60–70% of daily energy expenditure.
What is the difference between BMR and TDEE?
BMR is calories burned at rest. TDEE is BMR plus digestion, daily movement, and exercise. Use TDEE, not BMR, as your calorie target — eating at BMR means eating only two-thirds of what your body needs.
Which BMR formula should I use?
Mifflin-St Jeor is the modern standard and most accurate for the general population. Harris-Benedict is older and tends to overestimate by 5%. Katch-McArdle is best if you know your body fat percentage because it uses lean body mass directly.
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