This calculator can be used to estimate your Total Daily Energy Expenditure (TDEE).
BMR estimation formula:
- Exercise: 15-30 minutes of elevated heart rate activity.
- Intense exercise: 45-120 minutes of elevated heart rate activity.
- Very intense exercise: 2+ hours of elevated heart rate activity.
What is TDEE?
TDEE stands for total daily energy expenditure. It is the total energy that a person uses in a day. TDEE is hard to measure accurately and varies day by day. More often, it is estimated using factors such as a person's basal metabolic rate (BMR), activity level, and the thermic effect of food.
Basal metabolic rate:
BMR is a person's energy usage rate while at rest in a temperate environment when the digestive system is inactive. In other words, it is the minimum energy needed to maintain a person's vital organs only.
Activity level is a factor that is based on the amount of activity a person undergoes. This includes deliberate exercise as well as other activities that a person may undergo as part of their job or typical daily activities. These factors are more specifically referred to as the thermic effect of activity, and non-exercise activity thermogenesis (energy expended for non-sleeping, eating, or sports-like exercise).
Thermic effect of food:
The thermic effect of food, also referred to as specific dynamic action, is the amount of energy required by the body to process and use food. It is sometimes estimated as 10% of food energy intake, but this can vary significantly depending on the type of food consumed. Protein, for example, has a far larger thermic effect than dietary fat, since it is more difficult to process.
How is TDEE calculated?
TDEE is calculated based on the factors described above. The calculation usually begins with an estimation of basal metabolic rate (BMR), which is based on the use of equations that have been developed for this specific purpose. This includes physical characteristics such as age, gender, height, and weight.
Some of the more commonly used equations for estimating BMR include the Mifflin St-Jeor Equation, Harris-Benedict equation, and Katch-McArdle Formula. They are generally pretty similar, but the Katch-McArdle Formula, for example, which takes metabolic activity (resulting from differences between lean body mass and body fat) into account, can be more accurate for lean persons.
Once BMR is calculated, it is typically multiplied by an activity level factor, which is based on factors such as exercise and whether a person has a sedentary or very active job.
Other factors that can be considered in the calculation include the thermic effect of food, though this is not always factored into the calculation, and has a relatively smaller impact than BMR and activity level.