How it works
A MET (metabolic equivalent) compares an activity's energy cost to sitting at rest, which is defined as 1 MET, about 1 kcal per kilogram of body weight per hour. Brisk walking at 4.3 METs burns about 4.3 times your resting rate.
MET values here come from the Compendium of Physical Activities, the standard research reference. Calories are MET × body weight in kg × hours. The "net" figure subtracts what you would have burned at rest anyway.
Actual burn varies with fitness, effort, terrain and body composition, and fitness trackers use their own methods, so expect some difference. Results are estimates, not medical advice.
Formula
Calories = MET × weight (kg) × duration (hours)
Questions people ask
How many calories does walking burn?
Brisk walking at 3.5 mph burns roughly 4.3 kcal per kg per hour, about 150 calories in 30 minutes for a 154 lb (70 kg) person. Heavier people burn more for the same walk.
What does MET stand for?
Metabolic equivalent of task. One MET is the energy used sitting quietly; an activity rated 8 METs uses about eight times as much.
Why do fitness trackers show different numbers?
Trackers combine heart rate, motion and their own algorithms, and some report total calories while others report only active calories. Both approaches are estimates.