How it works
The Mifflin-St Jeor equation estimates your Basal Metabolic Rate — the energy your body needs at complete rest. Multiplying BMR by an activity factor gives your Total Daily Energy Expenditure (TDEE), which is how many calories you need to maintain your current weight.
Male BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 | Female BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
This is an estimate. Individual metabolism varies. Consult a healthcare professional for personalized dietary advice.
How do I calculate daily calorie needs?
To calculate daily calorie needs, first find your Basal Metabolic Rate (BMR) with the Mifflin-St Jeor formula, then multiply it by an activity factor. Example: a 30-year-old man, 170 cm, 70 kg, with light activity has a BMR of 1,618 kcal and a daily need (TDEE) of 2,224 kcal.
Steps to calculate daily calorie needs
- Calculate BMR for men: 10 × weight(kg) + 6.25 × height(cm) - 5 × age + 5.
- Calculate BMR for women: 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 161.
- Choose an activity factor from 1.2 (sedentary) to 1.9 (extra active) that matches your weekly exercise.
- Multiply BMR by the activity factor to get Total Daily Energy Expenditure (TDEE).
- Round the result; this is roughly the calories needed to maintain your current weight.
Calorie formula (Mifflin-St Jeor)
Men: BMR = 10W + 6.25H - 5A + 5 | Women: BMR = 10W + 6.25H - 5A - 161 | TDEE = BMR × activity factor
- W = weight in kilograms
- H = height in centimeters
- A = age in years
- activity factor = 1.2 to 1.9 depending on exercise frequency
Example BMR and TDEE
| Profile | Activity | BMR (kcal) | TDEE (kcal) |
|---|
| Male, 30, 170cm, 70kg | Light (1.375) | 1,618 | 2,224 |
| Female, 28, 160cm, 55kg | Moderate (1.55) | 1,249 | 1,936 |
| Male, 45, 175cm, 85kg | Sedentary (1.2) | 1,724 | 2,068 |
| Female, 35, 165cm, 60kg | Active (1.725) | 1,295 | 2,234 |
| Male, 22, 180cm, 75kg | Moderate (1.55) | 1,770 | 2,744 |
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is the energy your body needs at complete rest just to keep organs functioning. TDEE multiplies BMR by an activity factor to include the calories burned through daily movement and exercise, so TDEE is always equal to or higher than BMR.
Why does the formula subtract 161 for women but add 5 for men?
The Mifflin-St Jeor equation was derived from measured metabolic data and found that, for the same weight, height and age, women's average BMR runs lower than men's due to differences in typical body composition, so the constant term differs by sex.
How do I lose or gain weight using TDEE?
Eating below your TDEE creates a calorie deficit that typically leads to weight loss over time, while eating above it creates a surplus that leads to weight gain. A common approach is a 300 to 500 kcal daily deficit or surplus, adjusted based on results.
Is this formula accurate for everyone?
It is a population-average estimate. Actual metabolism varies with muscle mass, genetics, hormones, and health conditions, so two people with identical inputs can have different real BMR. Treat the result as a starting point, not an exact number.
This calculator estimates BMR and TDEE using the Mifflin-St Jeor formula and standard activity multipliers; it is not a medical assessment and does not account for individual metabolic conditions, medications, or body composition. Consult a doctor or registered dietitian before making significant dietary changes.