Mifflin St. Jeor Calculator

The Mifflin-St. Jeor calculator (or equation) calculates your basal metabolic rate (BMR), and its results are based on an estimated average. Basal metabolic rate is the amount of energy expended per day at rest (how many calories you would burn on bed rest).

Use this activity + Mifflin St. Jeor calculator to estimate your BMR and daily caloric burn (or Total Daily Energy Expenditure).

Mifflin St. Jeor Formulas:

Men - 10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) + 5
Women - 10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) – 161

(Currently these are the only formulas available)

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Instructions for Calculator


Click the menu button and select (US) Standard Units or Metric Units.


Select your biological sex and enter your stats (height, weight, age).


Now you have your BMR and estimates of your daily burn depending on your activity level.


Finally enter your activity level to get your estimated daily burn. Use the Standard guide below find your activity level multiplier OR take our free quiz to get an estimate!

Standard Activity Level Multipliers

BMR X 1.2: If you are sedentary = little to no exercise in a day
BMR X 1.375: If you are slightly active = light exercise/sports 1-3 days/week
BMR X 1.55: If you are moderately active = moderate exercise/sports 3-5 days/week
BMR X 1.725: If you are very active = hard exercise/sports 6-7 days a week
BMR X 1.9: If you are extra active = very hard exercise/sports and physical job OR 2x training

LEIGH'S TIP:  There is nothing inaccurate about the Standard Activity Level Multipliers; however, the explanation leaves many people confused. In addition to being confused people can  easily assume their activity level is higher than the reality. For example, if you train 6-7 days per week and have a desk job, you could still have an activity factor of 1.2.


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Quiz: Find Your Activity Level

Use the quiz below to get a better estimate of your activity level multiplier. For a more detailed assessment read The Fat Loss Troubleshoot.

After completing the quiz use the calculator above to get your Total Daily Energy Expenditure estimate.

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