Estimate calories burned for hundreds of activities based on MET values, body weight and exercise duration.
The number of calories that the body burns during regular daily activities or exercise is dependent on various factors, so it is not an exact science. The results of this calculator (and any other) are based on standardized data that references an "average" person, so it is only an estimate.
Generally, the number of calories consumed, less calories burned through activities and basal metabolic rate (calories consumed - calories burned - BMR) will determine whether a person maintains, loses, or gains weight; theoretically, if the number is 0, the person will maintain their weight; if the number is negative, they will lose weight; if the number is positive, they will gain weight.
The number of calories a person burns by performing a given activity is dependent on many different factors. Most estimates involve the use of three key factors: body mass, duration of the activity, and the metabolic equivalent of a task (MET). The MET of various tasks have been widely studied, and our calculator estimates calories burned based on data made available through these studies.
A person's body mass affects how many calories they burn, even at rest. A person who is larger due to more muscle, fat, or height burns more calories. This is also true during exercise since the body has to do more work to provide energy to a larger person than it would to a smaller person. Thus, a person who weighs 200 pounds will burn significantly more calories running 1 mile than someone who weighs 100 pounds, given that other conditions remain the same.
Duration of exercise is another factor that affects calories burned. The longer a person performs an exercise, the more calories they will burn. However, the relationship is not as simple as it is with body mass because the intensity of the exercise matters.
Exercise intensity is another key factor that affects the number of calories burned. The more intense the exercise, the greater the number of calories burned. Exercise intensity is measured in a number of different ways, some of which are more precise than others.
Exercise intensity may be measured using heart rate. Heart rate provides an indication of how difficult it is for a person to complete an exercise. Generally, the higher a person's heart rate while performing an exercise, the more intense the exercise. However, people have variable resting heart rates as well as maximum heart rates, so heart rate is not a precise measure of intensity.
A more precise measure of intensity involves the measurement of a person's oxygen consumption during exercise. Oxygen consumption and the intensity of exercise have a linear relationship; as exercise intensity increases, oxygen consumption increases. Thus, oxygen consumption during exercise, as compared to oxygen consumption at rest, provides us with a good representation of the metabolic requirements of a given exercise.
Oxygen consumption is measured in MET (metabolic equivalent of a task). The MET is the ratio of the rate at which a person expends energy (relative to their body mass) while performing a given physical task compared to a reference. By convention, the reference is based on the energy expended by an "average" person while they are sitting quietly, which is roughly equivalent to 3.5 mL of oxygen per kilogram per minute.
This value was derived experimentally by measuring the MET of a healthy 40-year-old male who weighed 70 kg. This is the baseline, meaning that a MET value of 1 represents the energy expended by an average person at rest. Thus, an activity that has a MET value of 2 requires twice as much energy as an average person expends at rest; a MET value of 8 requires eight times as much energy, and so on.
This calculator estimates calories burned using the following equation:
Where time is in the unit of minutes and body weight is in the unit of kilograms.
Many studies have been conducted to determine the number of calories expended while conducting certain activities. Our calculator uses data from these studies to determine the MET for certain activities, along with the equation above, to estimate calories burned given the duration an activity is performed and body mass.
| Intensity Category | MET Range | Example Activities |
|---|---|---|
| Light Intensity | 1.0 - 3.0 MET | Sleeping, watching TV, reading, slow walking, cooking |
| Moderate Intensity | 3.0 - 6.0 MET | Brisk walking, cycling slow, golf, dancing, tennis doubles |
| Vigorous Intensity | 6.0+ MET | Running, fast cycling, swimming laps, basketball, rope jumping |
For those interested in burning fat, it is worth noting that exercise intensity affects the type of fuel (carbohydrates, fats, protein) that the body uses. Thus, it is possible to regulate exercise intensity to influence the type of energy that the body uses. Generally, lower intensity exercises burn more fat, so if a person's goal is to burn fat, they should perform low intensity exercises for longer durations. As a person's exercise intensity increases, the body shifts from using fats to provide energy to using carbohydrates instead.
The accuracy of this calculation is significantly affected by MET. By convention, 1 MET is roughly equivalent to expending 1 Calorie per kilogram of body weight per hour or consuming 3.5 mL of oxygen per kilogram of body mass per minute. This convention was derived based on a single specific subject: a healthy 40-year-old male who weighed 70 kilograms.
A person's resting metabolic rate (RMR) is highly dependent on a number of factors such as lean body mass, age, health status, and more. Thus, calculations for an individual whose RMR varies significantly from that of the subject used as a reference will be less accurate; some studies have shown that the conventional 1 MET value overestimates oxygen consumption at rest by up to 20-30% on average.
The estimate is also affected by the fact that MET values were derived under the assumption that the activity is performed at a constant rate. For example, playing tennis for 1 hour can involve taking breaks between games, resting, chatting, etc., meaning that the activity is only truly performed for a shorter duration.
The only way to get a highly accurate number is for an individual to go to a lab that measures all of the necessary factors such as their maximum oxygen capacity, maximum heart rate, and more in order to serve as their own reference. MET is more effectively used as an index of intensity rather than for estimating calories burned for a specific individual.