You can get a rough estimate of the calories you will expend in many activities with a simple formula developed by physiologists using a yardstick known as the Metabolic Equivalent, or MET. A single MET represents the amount of energy used at rest. The University of South Carolina’s Arnold School of Public Health maintains what it calls the Compendium of Physical Activities, which gives the MET value of an array of sports, exercises and everyday tasks. It’s basically a list of how much extra energy gets used if you run a 10-minute mile or spend time raking leaves.

The list can be downloaded from prevention.sph.sc.edu/tools/compendium.htm.

To estimate calorie usage, find your activity (or the closest thing to it) on the list and multiply its MET value by your weight in kilograms. For example, take a woman who weighs 124 pounds (about 56 kilograms) and uses a stationary bicycle at moderate effort, which has a MET value of 7. Multiply 7 times 56 and you’ll learn that an hour on that bike would burn about 392 calories, or 6.5 calories per minute.

Keep in mind, the MET values are drawn from population studies and don’t account for many of the individual differences that determine your actual calorie usage.