Calories Burned Calculator

Every movement costs energy, and the amount depends mainly on how hard the activity is, how long it lasts and how much you weigh. This calculator uses metabolic equivalents (METs), the standard unit researchers use to compare the intensity of different activities, to turn those three inputs into an estimate of Calories burned.

Factors affecting calories burned

Body size is the biggest personal factor. Moving a heavier body takes more work, so a 200-pound person burns roughly a third more Calories than a 150-pound person doing the same activity for the same time. That is why every result here scales directly with weight. As people lose weight, they burn fewer Calories for the same workout, one reason weight loss tends to slow over time.

Intensity is the biggest factor you control. Walking slowly uses under 3 METs, while running at 8 miles per hour uses about 12. Within a single activity, speed, incline, resistance and the amount of rest between efforts all change the cost. Swimming hard laps burns far more than a leisurely paddle, and a basketball game more than shooting baskets.

Duration multiplies everything. A moderate activity sustained for an hour can burn as much as a short burst of very hard exercise, which is why consistent, longer sessions of walking or cycling can be as effective for energy balance as brief intense workouts.

Body composition plays a role. Muscle tissue is more metabolically active than fat, so people with more muscle use somewhat more energy at rest and during exercise. Strength training that builds or preserves muscle therefore supports energy use beyond the workout itself.

Age and sex influence metabolism through their effect on muscle mass and hormones. Resting metabolic rate generally declines slowly with age as muscle mass falls, and men on average burn more than women of the same weight because they tend to carry more lean tissue. MET-based estimates do not adjust for these differences, so they can overestimate the burn for older adults and smaller women.

Fitness and efficiency matter as well. As you become more practiced at a movement, you perform it with less wasted effort and a lower heart rate, so the same task can cost slightly fewer Calories than it did when you started. Beginners on a rowing machine or swimming laps often work much harder than experienced athletes at the same pace.

Environment adds or subtracts effort. Walking uphill, on sand or snow, or into a strong wind takes more energy than walking on a flat, firm path. Very hot or cold conditions also raise energy use slightly as the body works to regulate its temperature.

After vigorous exercise, the body continues to use extra oxygen for a while to restore itself, an effect called excess post-exercise oxygen consumption (EPOC). The extra burn is real but modest, usually a small percentage of the Calories used during the workout itself.

Finally, exercise is only one part of daily energy use. Most Calories go to keeping the body alive at rest, the basal metabolic rate, and a further portion goes to digesting food. Everyday movement such as standing, fidgeting, walking around the house and doing chores, known as non-exercise activity thermogenesis, can vary by several hundred Calories a day between people and is easy to overlook.

Calculating calories burned

A MET is the ratio of the energy used during an activity to the energy used sitting quietly. Sitting still is 1 MET; an activity rated at 4 METs uses four times as much energy as rest. Researchers have measured the oxygen cost of hundreds of activities and collected them in the Compendium of Physical Activities, the source of the approximate values used here.

Because one MET corresponds to about 3.5 milliliters of oxygen per kilogram of body weight per minute, and the body releases close to 5 Calories for every liter of oxygen it uses, the energy cost of any activity can be estimated from its MET value, body weight and time.

For example, a 150-pound (68 kg) person walking slowly at about 2 miles per hour (2.8 METs) for 45 minutes burns about 2.8 × 3.5 × 68 ÷ 200 × 45 = 150 Calories. Running at about 6 miles per hour (9.8 METs) for the same time would burn about 525 Calories.

These figures include the energy you would have burned anyway at rest during that time. To estimate only the extra energy from exercise, subtract 1 MET from the activity's value before calculating.

Calories = MET × 3.5 × body weight (kg) ÷ 200 × minutes

MET

metabolic equivalent of the activity (1 MET = resting)

One MET is defined as 3.5 mL of oxygen per kilogram per minute, and each liter of oxygen used releases about 5 Calories, which gives the 3.5 ÷ 200 factor.

Frequently asked questions

Sources

• Compendium of Physical Activities
• CDC – Physical Activity Basics
• HHS – Physical Activity Guidelines for Americans