What Are METs? How Calories for Any Activity Are Worked Out

A MET (metabolic equivalent of task) expresses the energy cost of an activity as a multiple of sitting at rest. Sitting quietly is 1 MET. Walking briskly is about 4.8. Running at a 10-minute-mile pace is 9.3. Multiply by your body weight and the time spent, and you have an estimate of the calories the activity used.

Where MET values come from

Researchers measure the oxygen people use while doing an activity, usually with a breath analyser, and divide it by the oxygen used at rest. Those measurements are gathered in the Compendium of Physical Activities, first published by Barbara Ainsworth and colleagues in 1993 and updated in 2000, 2011 and, most recently, in 2024 by Stephen Herrmann and colleagues in the Journal of Sport and Health Science. The 2024 adult edition lists more than a thousand activities, each with a five-digit code, from sleeping to marathon running, and separate compendiums now cover older adults and wheelchair users.

A few examples from the 2024 adult list:

Activity	Code	METs
Yoga, general	02175	2.3
Walking, 2.8–3.4 mph	17190	3.8
Weight training, 8–15 reps, several exercises	02054	3.5
Walking, 3.5–3.9 mph, brisk	17200	4.8
Cycling, moderate pace	01016	7.0
Running, 6–6.3 mph (10 min/mile)	12050	9.3
Swimming laps, freestyle, fast	18230	9.8
Jump rope	02068	11.0

You can look up any of these, and many more, in the MET calculator.

The formula

The standard conversion is:

calories = MET × body weight (kg) × duration (hours)

It rests on the definition of 1 MET as 3.5 millilitres of oxygen per kilogram per minute, which works out to roughly 1 calorie per kilogram per hour. So a 70 kg person running for 30 minutes at 9.3 METs burns about 9.3 × 70 × 0.5 ≈ 326 calories.

The mistake most calculators make

That 3.5 ml figure was measured decades ago on a single 40-year-old, 70 kg man. Research since then — including a 2005 study in the Journal of Applied Physiology by Byrne and colleagues titled “Metabolic equivalent: one size does not fit all” — has shown that the true resting rate of many people is lower, often noticeably so in women, older adults and people with more body fat. For them, the standard formula overstates the calories an activity burns.

The 2024 Compendium authors recommend correcting for this by using a person’s own resting rate. That is what the TDEE Meter tools do: 1 MET is set to your estimated BMR per hour, so the same run produces a figure that fits your body rather than the reference man’s.

Total versus extra calories

There is a second, quieter error. The formula gives the total energy used during the activity, including the energy you would have burned anyway just by being alive. If you add that total on top of a daily figure that already includes your resting burn, you count those resting minutes twice.

For a single 30-minute session the difference is small, about one MET’s worth. Over a week of workouts it adds up. Calculators that build a daily total, like the TDEE calculator, should add only the extra: (MET − 1) × your hourly resting rate × hours.

Moderate and vigorous, in METs

Public health guidelines define intensity in METs: light activity is under 3, moderate is 3 to 5.9, and vigorous is 6 or more. The U.S. Physical Activity Guidelines recommend 150 to 300 minutes of moderate or 75 to 150 minutes of vigorous activity each week, or a mix. A rough way to count: one vigorous minute equals two moderate minutes.

How fitness watches compare

Watches start from the activity type, which is essentially a MET value, and adjust it with your heart rate and movement data. For steady cardio such as running or cycling they can be closer than a table; for lifting and intervals heart rate is a weaker guide and estimates vary more. Either way, treat the number as an estimate and let your weight trend over weeks have the final say.