A half hour of lifting costs somewhere between 90 and 250 calories, depending on how heavy you go and how long you rest between sets. That is less than most people assume and less than half an hour of running. Lifting is still one of the best things you can do for your body composition, and the reason has almost nothing to do with the calories burned in the session.
Why the number is lower than it feels
Strength training is intense in bursts and mostly idle in between. A hard set lasts 30 seconds. The rest that follows lasts two or three minutes.
Add it up across an hour in the gym and the actual working time might be eight minutes. That is why an hour of lifting rarely matches an hour of steady cardio for energy spent, even though it feels considerably harder while you are doing it.
The variables that move the figure are the ones you would expect. Heavier loads and bigger movements cost more. Shorter rests raise the average. Squats and deadlifts cost far more than curls, because they involve more muscle and more of you moving.
The afterburn is real and modest
Hard training raises your metabolic rate for a while afterwards, as your body restocks fuel and repairs tissue. The technical name is excess post-exercise oxygen consumption, and the fitness industry has oversold it for twenty years.
It exists. It is measurable. It is also worth tens of calories, not hundreds, and it is largest after genuinely hard sessions rather than a comfortable one. Treat it as a small bonus rather than a reason to choose weights over cardio.
The real payoff is the muscle
This is where lifting earns its place.
Muscle tissue costs energy to maintain. Build more of it and your resting burn rises, which is a small effect per kilogram but a permanent one that applies every hour of every day, including while you sleep.
More importantly, lifting changes what you lose during a diet. Run a deficit without resistance training and a meaningful share of the weight that comes off is muscle. Keep lifting and your body has a reason to hold onto it, so more of the loss comes from fat. Same number on the scale, different body underneath, and a higher maintenance figure at the end of it.
That is the case for weights, and it does not depend on the calorie count of the session at all.
Lifting compared with cardio
Cardio wins on calories per session. It is not close, and anyone claiming otherwise is arguing against a stopwatch.
Lifting wins on what happens to your body composition, on strength, on bone density, and on how much muscle survives a cut.
So do both. Lift two or three times a week, keep some cardio for your heart and for the extra energy expenditure, and stop treating it as a competition. Our comparison of the calories burned running puts the cardio side in context.
Getting more out of the session
Prioritise compound movements. Squats, deadlifts, presses and rows recruit the most muscle for the time spent.
Shorten your rest periods if energy expenditure is the goal, or pair exercises as supersets. Be aware this trades away some strength work, so it is a choice rather than an upgrade.
Add weight or reps over time. Progressive overload is what actually builds muscle, and muscle is the part that pays you back later.
Do not chase the calorie readout on your watch. Wrist devices handle lifting particularly badly, because heart rate rises from strain rather than sustained aerobic work and the model reads that as more energy than it costs. Our piece on why trackers overestimate explains what goes wrong.
What this means for your intake
Set your intake from your maintenance calories and let the scale correct you. Do not add food for a lifting session on the assumption it burned 600 calories, because it almost certainly did not.
Keep protein high, particularly while cutting, since that is what lets the training protect your muscle. And accept that the scale moves slowly when you lift, because muscle gained partly offsets fat lost. That is the trade working, not failing. Our guide to body recomposition covers how to read progress when the scale refuses to move.