How many calories to gain muscle?

To gain muscle you eat above maintenance, but the size of the surplus is the whole decision, and bigger is not better here.

Start by finding your maintenance calories, then add a modest surplus on top. In the example above a moderately active man sits near 2,640 a day, so a lean surplus around 2,900 is the target. That works out to roughly half a pound of body weight a week.

The temptation is to add a lot more, a full 500 or beyond, on the theory that more food means more muscle. It mostly means more fat. Your body can only build muscle so fast, and any calories past that ceiling get stored, not turned into biceps. A smaller surplus means a higher share of what you gain is actual muscle and a lower share is fat you will have to diet off later.

Two things gate muscle gain more than the exact calorie number: enough protein and progressive overload in the gym. The surplus is permission to grow. The training is the request. Miss either and extra calories just make you heavier.

Weigh yourself weekly and watch the trend. If you are gaining faster than about a half to three quarters of a pound a week, trim the surplus a little. Put your stats in the calculator to find your maintenance, then add from there.