Workout Calorie Burn Estimator

Calories burned in a workout depend on your body weight, the activity's intensity, and duration. Generic charts assume a 150-pound person at moderate effort, which is wrong for most people in at least one of those dimensions. The MET (metabolic equivalent of task) system gives you a way to compute your specific number.

Select an activity from the list (each tagged with its MET value from the Compendium of Physical Activities), enter your weight and duration, and the calculator returns estimated calories burned. The formula is simple — calories per minute = (MET × 3.5 × weight in kg) / 200 — but the value comes from the activity database, which covers more than 800 specific activities at calibrated intensities.

Useful for setting calorie targets, comparing exercise modalities, and reality-checking fitness tracker estimates (which are often optimistic by 20–30% because manufacturers know users like high numbers).

The MET system formalizes what physiologists have measured in metabolic chambers for decades. Each activity gets a number representing its energy cost relative to sitting at rest. The Compendium of Physical Activities, published and periodically updated by Ainsworth and colleagues, catalogs over 800 activities with measured or estimated MET values. The conversion to calories uses the relationship 1 MET ≈ 1 kcal/kg/hour — so a 70-kg person at 4 METs (brisk walking) burns roughly 4 × 70 = 280 kcal/hour. The calculator's formula is the standard cal/min = MET × 3.5 × kg / 200, which produces the same answer with explicit units.

Worked example: a 165-lb (75 kg) person does 30 minutes of moderate cycling at 7 METs, then 20 minutes of running at 6 mph (~10 METs). Cycling: 7 × 3.5 × 75 / 200 = 9.2 kcal/min × 30 min = 275 kcal. Running: 10 × 3.5 × 75 / 200 = 13.1 kcal/min × 20 min = 263 kcal. Total 538 kcal. A fitness tracker on the same person doing the same workout will often report 650-700 kcal, an overestimate of 20-30%. The MET-based calculation is the conservative ground truth; trackers tend to inflate because users prefer big numbers.

Limits worth flagging: MET values are population averages from chamber-based measurements. Individual mechanical efficiency varies — a trained runner expends less energy at 8 mph than an untrained one, because their stride is more economical. Body composition affects energy cost too. The same MET-based calculation can be off by 15-20% for any specific individual, but it's still more accurate than most consumer trackers and a much better default than ignoring weight entirely. If you need precise numbers (weight loss research, performance fueling), only direct measurement (calorimetry, DEXA-corrected calculations) gets there.

The trickiest activity to estimate is weight training, where MET values vary enormously based on intensity, rest periods, and exercise selection. Light circuits at 3-5 METs are accurate; intense compound lifts with short rest can be 6-8 METs. Most calculators use one number, which is wrong on both ends. For weight training specifically, fitness trackers using heart rate aren't more accurate — they over-count because heart rate elevates from cardiovascular response to lifting effort even when caloric expenditure is modest. The honest answer: weight-training calorie estimates are noisy, no matter the source.