Estimate calories burned during exercise based on activity type, duration, and your weight.
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This calculator uses MET (Metabolic Equivalent of Task) values — a standardized measure of how many calories an activity burns relative to resting metabolism. Multiplying the MET value by your body weight and exercise duration gives a solid estimate of calories burned. Actual results vary by intensity, fitness level, and individual metabolism, but MET-based estimates are the standard used by most fitness trackers and apps. This calculator uses standardized MET (Metabolic Equivalent of Task) values drawn from exercise science research, which assign each activity — from walking to competitive sports — a fixed intensity score, then multiplies that by body weight and duration to produce an estimate, the same basic approach used by most fitness apps and wearable devices behind the scenes. Comparing results across multiple activities over time is generally more useful than trusting any single session's exact number. Body weight also changes gradually, so it's worth revisiting the input occasionally for continued accuracy.
Anyone who has compared the calorie count from a treadmill display, a fitness watch, and a phone app for the exact same workout has probably noticed the numbers rarely match — sometimes by a wide margin. This isn't necessarily a sign that any of them are "wrong"; it reflects genuine differences in the underlying estimation method and, more importantly, in the personal data each device actually has access to.
This calculator uses MET (Metabolic Equivalent of Task) values, a standardized system where 1 MET represents the energy cost of sitting quietly, and each activity is assigned a multiple of that baseline — walking briskly might be rated around 3.5 METs, while running at a fast pace can exceed 10 METs. The published MET values used across fitness science, including the Compendium of Physical Activities maintained by researchers at Arizona State University, come from studies measuring average oxygen consumption during each activity across groups of people, then converted to an estimated calorie burn using body weight, since heavier bodies expend more energy performing the same movement.
The main source of variation between devices is exactly this personalization: a MET-based calculator like this one only needs weight and duration, while a heart-rate-based fitness tracker also factors in real-time heart rate, and the most sophisticated devices add age, resting heart rate, and even estimated VO2 max — each additional input can shift the estimate, sometimes significantly, especially for atypical body compositions like very muscular or very lean individuals, where MET-table estimates tend to be less accurate than for an average body composition.
None of these estimates, from any device, are as precise as a lab-based indirect calorimetry test — the actual gold standard, which measures oxygen consumption and carbon dioxide production directly. For everyday tracking and comparing workouts against each other over time, though, a consistent estimation method (even an imperfect one) is more useful than chasing perfect accuracy from a single number.
It's a ratio comparing the energy cost of an activity to the energy cost of sitting quietly at rest.
Trackers use different sensors and algorithms (heart rate, motion, sometimes both), while this calculator uses standardized MET values — both are estimates, and some variation between methods is normal and expected.
Heavier bodies require more energy to move, so calorie burn scales with body weight for the same activity.