How to estimate your TDEE with Mifflin–St Jeor
Your basal metabolic rate (BMR) is the energy you burn at rest; total daily energy expenditure (TDEE) is BMR multiplied by an activity factor. Mifflin–St Jeor is a well-validated equation for estimating BMR from a few metrics.
- Enter sex, age, height, and weight in your preferred units.
- Pick an activity level from sedentary to very active — this sets the multiplier.
- Read your BMR and TDEE with the full equation shown.
- Add a protein target (optional) to see grams per day at your chosen ratio.
Worked example: 35 years, 80 kg, 180 cm, male, moderate activity
Using Mifflin–St Jeor for a 35-year-old male, 80 kg and 180 cm, at a moderate activity level (×1.55):
- BMR — (10×80) + (6.25×180) − (5×35) + 5 = 1,755 kcal/day.
- TDEE — 1,755 × 1.55 = ≈ 2,720 kcal/day.
- For women, the equation ends in −161 instead of +5.
This is a population-average estimate, not a calorie prescription — real needs vary. Enter your own metrics above.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR (basal metabolic rate) is the energy your body uses at complete rest. TDEE (total daily energy expenditure) is BMR multiplied by an activity factor to account for movement and exercise, so it estimates the energy you actually use in a day.
What is the Mifflin–St Jeor equation?
It is a widely used, well-validated formula for estimating BMR from weight, height, age, and sex: (10 × kg) + (6.25 × cm) − (5 × age) + 5 for men, or − 161 for women. TDEE is that BMR times an activity multiplier.
Which activity level should I choose?
Pick the multiplier that best matches a typical week — sedentary (little exercise) up to very active (hard training most days). Activity level is the biggest source of variation, so choose honestly; the tool shows how it changes your TDEE.
Is my TDEE a calorie target?
No. It is an educational estimate of energy expenditure, not a prescription for how much to eat. Any calorie or weight goal should be set with a qualified professional; this tool never recommends a target.
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