A typical gym session burns somewhere between 200 and 500 calories per hour, depending on what you’re doing and how hard you’re working. A lighter weightlifting routine sits closer to the 200 range, while intense cardio or circuit training can push well past 400. The variation is huge because “a gym session” means wildly different things to different people.
Calorie Burn by Workout Type
Every exercise has a standardized intensity score called a MET value (metabolic equivalent of task), which researchers use to estimate energy expenditure. The higher the number, the more calories you burn per minute. Here’s how common gym activities compare:
- Vigorous weightlifting (heavy sets, compound lifts, short rest periods): 6.0 METs
- Squats and general resistance training (moderate effort): 5.0 METs
- Elliptical trainer (moderate effort): 5.0 METs
- Running on a treadmill at 6 mph (10-minute mile pace): 9.8 METs
To put those numbers in practical terms: a 150-pound person doing vigorous weightlifting for 45 minutes burns roughly 270 calories. That same person running at 6 mph on a treadmill for 45 minutes burns around 440. A 200-pound person doing the same weightlifting session burns closer to 360 calories, and treadmill running jumps to about 590. Body weight is one of the biggest factors in the equation, simply because moving a heavier body requires more energy.
The formula behind these estimates is straightforward: multiply the MET value by 3.5, then by your body weight in kilograms, and divide by 200. That gives you calories burned per minute. For most people, multiplying that by the length of your workout gets you a reasonable ballpark.
Why Your Number Could Be Higher or Lower
Two people doing the exact same workout can burn meaningfully different amounts of calories. Body weight is the most obvious reason, but it’s not the only one. Muscle tissue burns roughly 4.5 to 7 calories per pound per day at rest, while fat tissue burns far less. Someone with more muscle mass has a higher baseline metabolic rate, which translates to slightly more calories burned during exercise too.
Workout structure matters just as much. Rest periods are a hidden variable that most people overlook. If you spend 60 minutes in the gym but rest for 3 to 4 minutes between every set, your actual working time might be only 20 to 25 minutes. Compare that with someone doing supersets or circuit training with 30-second rest periods, and the calorie difference over the same hour is significant. Intensity within each set also plays a role: lifting at 80% to 90% of your max burns more than going through the motions at 50%.
Heart rate, fitness level, age, and even temperature all nudge the number in one direction or another. Fitter individuals tend to burn fewer calories doing the same workout because their bodies have become more efficient at performing it. This is one reason why a workout that left you drenched in sweat three months ago might feel routine now.
The Extra Calories You Burn After Leaving
Your calorie burn doesn’t stop the moment you rack your last weight. After intense exercise, your body continues consuming oxygen at an elevated rate to repair muscle tissue, restore energy reserves, and clear metabolic byproducts. This process, known as EPOC (excess post-exercise oxygen consumption), adds roughly 6% to 15% on top of whatever you burned during the workout itself. So if your session burned 300 calories, you can expect an additional 18 to 45 calories from the afterburn effect.
That bonus is modest for most workouts. Where it gets more interesting is after heavy resistance training. Research has shown that lifting at 80% to 90% of your maximum weight until exhaustion produces a significantly larger EPOC response than lighter exercise. Estimates for how long this elevated burn lasts range from 15 minutes to as long as 48 hours, though the bulk of it happens in the first few hours post-workout. High-intensity interval training produces a similar effect.
This is one reason strength training punches above its weight for long-term calorie management, even though the in-session calorie number looks lower than cardio. The combination of afterburn calories and the gradual increase in muscle mass shifts your daily energy expenditure upward over time.
Gym Machine Calorie Counters Are Inflated
If you’ve been relying on the number displayed on the treadmill or elliptical, you’re almost certainly overestimating. Cardio machines tend to overstate calorie burn by about 100 calories per 30 minutes of moderate exercise. Over a 45-minute or 60-minute session, that error adds up fast. The machines can’t account for your fitness level, body composition, or movement efficiency, so they default to generous assumptions.
Wrist-based fitness trackers are better but still imperfect, with error rates that vary by brand and exercise type. Heart rate chest straps paired with a good app tend to be the most accurate consumer option. If you’re tracking calories for weight management, shaving 15% to 20% off whatever your device reports gives you a more realistic estimate.
Quick Reference by Body Weight
These estimates assume a continuous 60-minute workout with typical rest periods:
- Moderate weightlifting, 150 lbs: roughly 275 to 325 calories
- Moderate weightlifting, 200 lbs: roughly 365 to 430 calories
- Vigorous weightlifting, 150 lbs: roughly 350 to 400 calories
- Vigorous weightlifting, 200 lbs: roughly 470 to 530 calories
- Treadmill running at 6 mph, 150 lbs: roughly 590 calories
- Treadmill running at 6 mph, 200 lbs: roughly 790 calories
- Elliptical (moderate), 150 lbs: roughly 300 calories
- Elliptical (moderate), 200 lbs: roughly 400 calories
These ranges don’t include afterburn calories. For a mixed session that combines 30 minutes of lifting with 20 minutes of cardio (which is how many people actually use the gym), a 150-pound person can expect to burn in the ballpark of 250 to 350 total calories, and a 200-pound person around 350 to 475.