This TDEE Calculator uses the Original Harris-Benedict, the Revised Harris-Benedict, the Mifflinf St Jeor, and the Katch-McArdle formulas to calculate your base metabolic rate (BMR) and total daily energy expenditure (TDEE). You can read more about the formulas used by the calculator, BMR, and TDEE below.

- Sedentary = BMR x 1.2 (little or no exercise, desk job)
- Lightly active = BMR x 1.375 (light exercise/activity 1-3 days/week)
- Moderately active = BMR x 1.55 (moderate exercise/activity 6-7 days/week)
- Very active = BMR x 1.725 (2-3 hours of hard exercise every day)
- Extremely active = BMR x 1.9 (hard exercise 2 or more times per day, or training for marathon, or triathlon, etc.)

Total Daily Energy Expenditure, AKA TDEE, is the total number of calories you use in 24 hours. It includes both your base calories (those needed to maintain bodily functions) and activity calories (calories added to base calories and needed to support daily activities). The TDEE can vary widely depending on age, weight, gender, activity level, and activities. Athletes and other very active people will have much a higher TDEE than sedentary individual. There is also a difference based on genetics, which determines a person's metabolic rate, although this tends to be slight.

This is the amount of calories a person needs to maintain his or her current body weight. There are many different formulas you can use to determine your maintenance calories, taking into account your age, sex, height, weight, lean body mass, and activity level.

The easiest method uses only total body weight:

While this method will give you a daily caloric range to aim for, it doesn't take into account individual metabolic factors, such as age, weight, activity level, gender and more.

- To lose weight, consume 12-13 calories per pound of body weight

- To maintain weight, consume 15-16 calories per pound of body weight

- To gain weight, consume 18-19 calories per pound of body weight

A more accurate method for determining your TDEE is to determine your basal metabolic rate (BMR) using your height, weight, age, and sex, then multiply the BMR by an activity factor to calculate your TDEE.

Base Metabolic Rate (BMR) is the number of calories your body requires for normal bodily functions, not including activity. These functions include such things as keeping your heart beating, inhaling and exhaling air and processing oxygen, digesting food, making new blood cells, maintaining body temperature, and the other metabolic processes. In simple terms, BMR is the energy required for the basic processes of life.

BMR can vary person to person depending on genetic and environmental factors. BMR is at its lowest during sleep and increases slightly when you eat in order to digest food. Having a higher percentage of lean mass (muscle) also increases your BMR, Because muscle uses more energy than fat, a muscular person will
have a higher BMR than a non-muscular person.

The Harris-Benedict formula is a method for calculating TDEE based on total body weight, height, age, and gender and it more accurate than the easy formula above. There are two forms of the equation, the original which was created in 1919 and the revised, which was don ein 1984 and is considered to be more accurate.

**Calculating your Base Metabolic Rate**

**Original Harris-Benedict Equation**

- Men: BMR = (13.7515 x weight in kg) + (5.0033 x height in cm) - (6.755 x age in years) + 66.473
- Women: BMR = (9.5634 x weight in kg) + (1.8496 x height in cm) - (4.6756 x age in years) + 655.0955

- Men: BMR = (13.397 x weight in kg) + (4.799 x height in cm) - (5.677 x age in years) + 88.362
- Women: BMR = (9.247 x weight in kg) + (3.098 x height in cm) - (4.33 x age in years) + 447.593

The Mifflin St Jeor equation was created in 1990 by some doctor name Mifflin (of course) and a bud of his St Jeor, neither of whom I can find any info on. In any case, it's regarded to be more accurate than either of the Harris-Benedict formulas

**Mifflin St Jeor Equation**

- Men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) + 5
- Women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) - 161

Both the Harris-Benedict and Mifflin-St Jeor formulas are based on total body weight and don't take into account lean body mass versus non lean mass (fat). The Katch-McArdle formula is used to predict Resting Daily Energy Expenditure (RDEE) which is the same as BMR. In order to use the Katch-McArdle formula, you have to have some idea of you body fat percentage. The formula is the same regardless of gender.

**Katch-McArdle Equation**

- RDEE = 370 + (21.6 * lean body mass in kg)