BMR Calculator
Calculate your Basal Metabolic Rate (BMR) — the number of calories your body burns at rest — using the Mifflin-St Jeor equation.
Your BMR
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Calories per Hour
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Calories per Minute
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Daily Energy (kJ)
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TDEE Estimates by Activity Level
Enter your details above to see TDEE estimates at each activity level.
How to Use the BMR Calculator
- Choose your unit system: Select either Metric (kg, cm) or Imperial (lb, in).
- Enter your details: Fill in your age, gender, weight, and height.
- View your results: Your BMR in calories per day, per hour, per minute, and in kilojoules appear instantly.
- Check TDEE estimates: See how many total calories you need at different activity levels.
Mifflin-St Jeor Formula
The Mifflin-St Jeor equation (1990) is considered the most accurate for estimating BMR:
- Men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) + 5
- Women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) - 161
BMR represents the minimum energy your body needs to maintain basic life functions — breathing, circulation, cell production, and nutrient processing — while at complete rest.
Factors That Affect BMR
| Factor | Effect on BMR |
|---|---|
| Age | BMR decreases ~1-2% per decade after 20 |
| Muscle Mass | More muscle = higher BMR |
| Gender | Men generally have higher BMR than women |
| Body Size | Larger bodies require more energy at rest |
| Genetics | Can account for up to 10% variation |
| Temperature | Cold exposure can increase BMR |
Frequently Asked Questions
What is the difference between BMR and TDEE?
BMR is the calories your body burns at complete rest (just to stay alive). TDEE (Total Daily Energy Expenditure) includes your BMR plus calories burned through physical activity and digesting food. TDEE is always higher than BMR and represents the total calories you need each day.
Should I eat below my BMR to lose weight?
It is generally not recommended to eat below your BMR, as this can slow your metabolism, cause muscle loss, and lead to nutritional deficiencies. For weight loss, aim to eat between your BMR and TDEE — typically 500 calories below your TDEE for a safe rate of about 1 pound per week.
How can I increase my BMR?
The most effective way to increase BMR is through resistance training (building muscle mass). Each pound of muscle burns approximately 6-7 calories per day at rest, compared to 2-3 for fat. Adequate protein intake, regular exercise, and proper sleep also support a healthy metabolic rate.