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
Quick calorie answers
What is the BMR of a 30-year-old man, 175 cm, 70 kg?
BMR is 1,649 kcal (10×70 + 6.25×175 − 5×30 + 5).
What is his daily calorie need (TDEE) with a sedentary lifestyle?
TDEE is 1,978 kcal (1,649 × 1.2 sedentary activity factor).
What is the BMR of a 25-year-old woman, 160 cm, 55 kg?
BMR is 1,264 kcal (10×55 + 6.25×160 − 5×25 − 161).
What is her daily calorie need (TDEE) if she's moderately active?
TDEE is 1,959 kcal (1,264 × 1.55 moderate activity factor, for 3 to 5 days of exercise per week).
Is eating 1,500 kcal a day a calorie deficit?
It depends on your own TDEE. For the two profiles above, TDEE runs 1,959 to 2,224 kcal, so 1,500 kcal would be a deficit for them — but someone with a smaller body or lower activity level could have a TDEE closer to 1,500 kcal. Calculate your own BMR and TDEE first, then compare against 1,500 kcal.
What is the TDEE of a 30-year-old man, 170 cm, 70 kg, with light activity?
TDEE is 2,224 kcal (BMR 1,618 × 1.375 light-activity factor).
For the same BMR, how much higher is TDEE with light activity than sedentary?
For a BMR of 1,649 kcal, sedentary (×1.2) gives 1,978 kcal and light activity (×1.375) gives 2,267 kcal — a difference of 289 kcal.
Which activity factor should I use if I exercise 3 to 5 days a week?
Use 1.55, the “moderately active” factor; 1.2 is sedentary, 1.375 is 1-3 days/week, 1.725 is 6-7 days/week, and 1.9 is very hard daily exercise.
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.