Learn what total daily energy expenditure is, how we calculate it, and how you can use it.

Your TDEE is the number of calories you use every day. Put simply, if you consume exactly your TDEE every day you would theoretically maintain a constant weight. Your TDEE consists of 4 key components:

- Basal Metabolic Rate (BMR): the amount of energy your body requires to run basic processes.
- Non exercise activity thermogenesis (NEAT): the energy expended from all the movements you do during the day not related to exercise.
- Thermic Effect of Food (TEF): the amount of energy required to extract energy from the food you consume.
- Exercise activity (EAT): the amount of energy you expend through exercise.

The pie chart shows approximately what proportion of your TDEE these four components are responsible for. If you are interested in reading more about TDEE we recommend checking out Fat Loss Forever by Peter Baker and Layne Norton.

The CaloCrunch calculator estimates TDEE using a combination of the most current TDEE equations, which are described below. If a bodyfat percentage is provided, all four equations are used to estimate TDEE and the average of these estimates is output. If a bodyfat percentage is not given, the average of the Mifflin-St. Jeor and Revised Harris-Benedict equations is output. These equations output an estimate of BMR, which is then adjusted to an estimate of TDEE based on your activity level.

The CaloCrunch planning tool uses an individual's current TDEE to estimate how many calories they should consume to achieve their specific weight goal over their specific duration of time. For simplicity, the planner assumes that an individual's current TDEE remains constant during their weight loss/gain, and that there are approximately 7700 calories per kg of mass (3500 calories per lb).

Mifflin-St. Jeor Equation

- For males:
`BMR = (6.25 x weight in kg) + (9.99 x weight in kg) – (4.92 x age) + 5`

- For females:
`BMR = (6.25 x height in cm) + (9.99 x weight in kg) – (4.92 x age) – 161`

Revised Harris-Benedict Equation

- For males:
`BMR = (13.397 × weight in kg) + (4.799 × weight in kg) - (5.677 × age) + 88.362`

- For females:
`BMR = (9.247 × weight in kg) + (3.098 × weight in kg) - (4.330 × age) + 447.593`

Katch-McArdle Equation

- For both male & female:
`BMR = (21.6 x lean body mass) + 370`

Muller Equation

- For males:
`BMR = (13.587 x lean body mass) + (9.613 x fat mass) - (3.351 x age) + 872`

- For females:
`BMR = (13.587 x lean body mass) + (9.613 x fat mass) - (3.351 x age) + 674`

Based on your current goals, you can adjust your daily calorie consumption to gain or lose weight. Typically, consuming less calories than your TDEE will result in weight loss, while consuming more calories than your TDEE will result in weight gain. Of course, your exact TDEE will vary from day to day. It is important to remember that the estimates of TDEE provided here are exactly that - estimates. The best way to understand your TDEE is to record your daily calorie consumption and weight over a long period of time.

Nevertheless, estimating your TDEE is a good first step towards weight loss, gain or maintenance. If you are planning on losing or gaining weight, check out the CaloCrunch planning tool which can be used to help you plan your calorie consumption and weight loss/gain over a period of your choice. A weight loss/gain of 0.5kg (1lb) per week is a safe upper limit to aim for. There are many guides out there describing effective approaches for losing or gaining weight. Estimating TDEE is just one step in the process and we recommend taking a look at diet and exercise programs such as:

- Fat Loss Forever by Peter Baker and Layne Norton
- The Art of Reverse Dieting by Mark Carroll