The number of calories you burn in a day depends primarily on your Basal Metabolic Rate (BMR) and your level of physical activity. Your BMR is the number of calories your body needs at rest to maintain vital functions like breathing, heart beating, and brain activity. To estimate your total daily calorie burn, or Total Daily Energy Expenditure (TDEE), your BMR is multiplied by an activity factor that accounts for your daily physical activity and exercise
How to Estimate Calories Burned Per Day
-
Calculate Basal Metabolic Rate (BMR):
This depends on your age, sex, weight, and height. For example, the Mifflin- St. Jeor equation is a commonly used formula to estimate BMR:- For men: BMR=10×weight (kg)+6.25×height (cm)−5×age (years)+5BMR=10\times \text{weight (kg)}+6.25\times \text{height (cm)}-5\times \text{age (years)}+5BMR=10×weight (kg)+6.25×height (cm)−5×age (years)+5
- For women: BMR=10×weight (kg)+6.25×height (cm)−5×age (years)−161BMR=10\times \text{weight (kg)}+6.25\times \text{height (cm)}-5\times \text{age (years)}-161BMR=10×weight (kg)+6.25×height (cm)−5×age (years)−161
-
Apply an Activity Multiplier:
This adjusts for your lifestyle and exercise level:- Sedentary (little or no exercise): BMR × 1.2
- Lightly active (light exercise/sports 1-3 days/week): BMR × 1.375
- Moderately active (moderate exercise/sports 3-5 days/week): BMR × 1.55
- Very active (hard exercise/sports 6-7 days/week): BMR × 1.725
- Extra active (very hard exercise or physical job): BMR × 1.9
-
Result:
The product of BMR and the activity multiplier gives your estimated total calories burned per day (TDEE), which typically ranges:- Men: about 2,000 to 2,450 calories/day
- Women: about 1,600 to 1,950 calories/day
These ranges exclude calories burned from exercise and vary with individual factors
Example
A 32-year-old woman weighing 70 kg who works a sedentary job but walks 5 times per week might have:
- BMR ≈ 1414 calories/day
- Activity factor ≈ 1.55 (moderate activity)
- TDEE ≈ 1414 × 1.55 = 2102 calories/day burned
Factors Influencing Calorie Burn
- Age: Calorie needs peak around age 25 and decline about 2% per decade due to loss of muscle mass
- Sex: Men generally burn more calories than women due to higher muscle mass
- Body composition: More muscle mass increases calorie burn
- Activity level: More physical activity increases calorie burn significantly
- Metabolic rate and genetics also play roles
Summary
To know how many calories you burn a day, calculate your BMR based on your personal stats, then multiply by an activity factor that reflects your daily movement and exercise. This gives your Total Daily Energy Expenditure (TDEE), the best estimate of your daily calorie burn including all activities
. Various online calculators can help you do this quickly and accurately. If you want a precise number tailored to your body and lifestyle, consider using a TDEE calculator or consulting a healthcare professional or registered dietitian.
