The Mifflin-St Jeor 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.
Below is our Mifflin St. Jeor Calculator. This will help you estimate your BMR and what your daily caloric burn could be. For your knowledge, here are the 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
Instructions for Calculator
Click the menu button and select US 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 guide below to help you pick your activity level multiplier OR take our free quiz!
Typical 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 Typical 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.