How Many Calories Does Strength Training Burn?

The short answer

Strength training is listed at 5.0 MET in the Compendium of Physical Activities for moderate effort with short rests. In calories that is the table below, produced by the calories burned calculator for a session of that length at a steady moderate effort.

Notice how the rest periods are already inside the number. A squat set is hard work, but the two minutes you spend between sets at 1.5 MET drag the session average down. That average is what the estimate describes.

Where the number comes from

Lifting uses the same MET arithmetic as every other activity here: kilocalories per minute = MET x 3.5 x body weight in kilograms / 200. Five MET is the Compendium's value for resistance training with moderate effort and short rests, which is what most gym sessions look like.

The honest limitation is that a MET value describes an average intensity, and lifting is not average. A session of heavy squats and a session of arm curls get the same estimate from a single MET, even though one is much harder work.

Why lifting costs less per minute than cardio

Per minute, steady cardio beats lifting: cycling at 7.5 MET, jogging at 7.0 and running at 9.8 all sit above the 5.0 MET of a typical weights session, and they have no rest periods pulling the average down. If the goal is energy spent during the session, cardio wins on every comparable duration.

What lifting buys instead is different. It is the strongest signal for keeping muscle while you lose fat, and it is the reason a deficit does not have to cost you strength. Judging a session only by its calorie number misses what it is for.

Is the afterburn real?

Partly. Hard training leaves oxygen consumption slightly elevated for hours afterwards, and that extra is called excess post-exercise oxygen consumption. It is real, it is measurable, and it is small: a few percent of the session's cost rather than a second session happening while you sit down.

The big numbers quoted for it usually come from small studies with wide error bars, or from comparing a hard session against sitting still rather than against the same time spent moving. Plan as though the session costs roughly what the table above says, and treat any afterburn as a rounding error.

Why the session average is the honest unit

Every figure on this page describes a whole session, which is why it disagrees with the number a smartwatch reports. Watches estimate from heart rate, and heart rate drifts upward through a session for reasons unrelated to work - heat, caffeine, adrenaline before a heavy set - so they tend to overstate lifting more than they overstate steady cardio.

Neither number is a measurement. If you want a single figure to plan around, use the session average here, and if you want to know whether your training is working, use the bar, the tape and the mirror rather than the calorie count.

Does muscle burn calories at rest?

Yes, and far less than the popular figure. Tissue measurements put skeletal muscle at roughly 13 kcal per kilogram per day at rest. The familiar claim that a pound of muscle burns 50 calories a day would imply about eight times that, which is why the claim keeps being corrected and keeps surviving.

Put in context: adding three kilograms of muscle - a serious multi-year project for most people - changes resting expenditure by roughly 40 kcal a day, about a tenth of a typical deficit. Worth having, and not a reason on its own to lift.

How to log a session honestly

The estimate is only as good as the duration you give it. Count from the first working set to the last, rest periods included, because that is what a session MET describes. Timing only the sets themselves and multiplying produces a number several times too high.

Compound lifts and short rests sit above the 5.0 MET average; isolation work, long chats between sets and a lot of standing around sit below it. If your training is genuinely hard and continuous - circuits, complexes, heavy squats with two minute rests - the true cost is higher than the table, and the calculator cannot know that unless you pick a harder activity.

What a weekly lifting habit adds up to

At 75 kg a 45 minute session is 295 kcal. Three a week is 885 kcal, about 0.11 kg of body weight at 7,700 kcal per kilogram. Four longer sessions reach 1,576 kcal and roughly 0.20 kg.

Read that table next to the running and walking pages and the picture is consistent: training, done at any realistic volume, is a modest part of weekly energy. It is the part that decides what your body is made of, which is a different and better reason to do it.

How to use the number

If you want a figure for your own session, the calories burned calculator takes body weight, duration and activity and returns per-minute, hourly and total costs. Enter the real session length including rests, and treat the result as the cost of the work rather than a budget you have earned back.

The more useful way to read it is comparatively. A 45 minute session at 75 kg is 295 kcal; the same time spent jogging is 414 kcal. The weights session is the one that keeps the muscle you are trying to keep, and that is the trade worth making deliberately rather than by accident.

One detail worth knowing: the calculator converts pounds to kilograms before the MET arithmetic runs, so choosing pounds or kilograms does not change the answer. Weigh yourself under the same conditions each time, because a five kilogram error moves the session estimate by around twenty calories.

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