Calories Burned Calculator

A MET, or metabolic equivalent of task, is defined as the energy cost of an activity expressed as a multiple of resting energy expenditure — one MET is roughly the cost of sitting quietly, and an activity rated at 8 METs uses about eight times that much energy per minute. Because it is a ratio rather than an absolute number, MET values scale naturally to a person’s size: multiplying by body weight is what converts the generic MET rating into an actual calorie estimate for a specific individual.

The MET values behind this calculator come from the Compendium of Physical Activities, a standardised reference catalogue first published by exercise physiologist Barbara Ainsworth and colleagues in 1993 and periodically updated since, most recently in a major 2011 revision. It was created to solve a real problem in exercise research — studies describing exertion in inconsistent, subjective terms — by giving researchers and clinicians a common, comparable intensity value for hundreds of specific activities, from walking speeds to particular sports and household chores.

MET values are population averages measured under controlled conditions, and individual energy cost for the same activity can easily vary by 20% or more depending on movement efficiency, fitness level, terrain, temperature and body composition — a trained runner typically uses less energy at a given pace than an untrained one, for instance, because movement economy improves with practice. Consumer fitness trackers add a further layer of error on top of this: they estimate energy expenditure indirectly from heart rate and motion rather than measuring oxygen consumption directly, and independent validation studies have repeatedly found they can be off by 20–50%, usually in the direction of overestimating.

Outside of consumer calorie counting, MET values are widely used in public health research to classify and compare physical activity levels across large populations — the basis, for example, of national guidelines that define “moderate” and “vigorous” activity in MET terms — and in clinical exercise prescription, where a target MET range helps set safe activity levels for people recovering from cardiac events or managing chronic conditions.