Calories Burned by Activity

Most exercise calorie estimates are built on the same formula the American College of Sports Medicine publishes: calories burned equals the activity’s MET value multiplied by body weight in kilograms multiplied by duration in hours. MET stands for Metabolic Equivalent of Task, where 1 MET is the energy your body uses at rest. Running at 8 mph carries a MET of 11.5, which means it burns 11.5 times as much energy per kilogram per hour as sitting still.

Calories Burned by Activity covers 38 exercises across six groups — Walking, Running, Cycling, Swimming, Gym and Other — sourced from the 2011 Compendium of Physical Activities (Ainsworth et al.). Each entry in the grouped selector shows its MET value so the comparison is visible before you commit to a choice. A brisk walk at 3.5 mph (MET 4.3) burns almost exactly the same calories per hour as low-impact aerobics (MET 5.0) at a given weight, which most people find surprising.

Worked Example: 8 mph for 30 Minutes

1. Select Running (8 mph / 7.5 min/mi)from the Running group, or press Load Sample to fill all three fields automatically.
2. Enter 70 in the weight field (kg selected by default). Tap the unit button to switch between kg and lbs — the value converts automatically and the calculation uses kilograms internally.
3. Enter 30 in the duration field, or tap the 30 min quick-preset chip.
4. The result appears immediately: 403 kcal. The breakdown panel shows the full arithmetic: 11.5 × 70 × 0.5 = 402.5, rounded to the nearest whole kilocalorie.
5. The three context cards below show 13.4 kcal/min,805 kcal/h and intensity categoryVigorous (any MET above 6).

The MET Formula and How It Rounds

The formula is kcal = MET × weight⊂kg × (minutes / 60). The result is rounded to the nearest whole kilocalorie. Weight entered in lbs is converted by dividing by 2.20462 before the multiplication, then the rounded kilogram value is shown in the breakdown panel so you can verify the conversion. Duration is capped at 600 minutes (10 hours); weight is capped at 500 kg. A zero or negative in either field returns the message “Weight must be a positive number.” or “Duration must be a positive number.”

When Not to Use This Tool Alone

MET values are population averages measured under lab conditions. Actual energy expenditure varies with fitness level, terrain, ambient temperature and individual metabolism, and can differ from the formula output by 20–30%. Swimming butterfly (MET 13.8) is the highest-intensity option in the table; walking slowly (MET 2.5) is the lowest. Intensity classification follows the WHO threshold: below 3 is Light, 3–6 is Moderate, above 6 is Vigorous. The tool does not account for the post-exercise oxygen consumption (EPOC) effect that elevates calorie burn for hours after a hard session.