The Harris Benedict Equation is a formula that was created from and by the research of James Arthur Harris and Francis Gano Benedict in 1919. Though it has been modified and changed over the years, it’s still the most widely used equation today that uses your Basal Metabolic Rate (BMR) in combination with your activity level to determine your total daily energy usage in calories. The only thing the Harris-Benedict Equation doesn’t take into consideration is lean body mass. People who are more lean need more calories than those with less leaner bodies. That being said, the Harris-Benedict Equation is extremely accurate for everyone except the extremely muscular (it will under estimate required calories) and the those who have a higher body fat percentage (it will over estimate required calories).

Harris-Benedict Equation

However, regardless of you being extremely muscular or extremely overweight, it’s still an excellent source to use to determine what your daily calorie intake should be in order to achieve your fitness goals.

In order to use the Harris-Benedict Equation, you first need to know your Basal Metabolic Rate, or BMR. You can get your BMR using the Apex Tough BMR Calculator.

Once you know your BMR, you then need to determine what your level of activity is. Use the chart below to determine your daily activity level, or continue scrolling to use our built in Harris-Benedict Equation calculator. Once you have determined your daily activity level, multiply your BMR by the respective number to know what your required daily calorie intake should be to maintain your current body weight.

How Your Required Daily Calorie Intake is Calculated

Sedentary
(little to no exercise)
BMR x 1.2
Lightly Active
(light exercise/sports 1-3 days a week)
BMR x 1.375
Averagely Active
(moderate exercise/sports 3-5 days a week)
BMR x 1.55
Very Active
(hard exercise/sports 6-7 days a week)
BMR x 1.725
Intensely Active
(extremely hard exercise/sports & physical job or multiple daily workouts)
BMR x 1.9

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