To build muscle, you need to eat roughly 5 to 20% more calories than your body burns each day. For most people, that translates to somewhere between 2,200 and 3,500 calories daily, though the exact number depends on your size, activity level, and training experience. The key is finding your personal maintenance level first, then adding a controlled surplus on top of it.
Finding Your Maintenance Calories
Before you can figure out how much extra to eat, you need to know how many calories your body uses just to maintain its current weight. This number is called your Total Daily Energy Expenditure, or TDEE. It accounts for everything your body does in a day: keeping your organs running, digesting food, walking around, and exercising.
Your TDEE is based on your age, sex, height, weight, and how active you are. A 25-year-old man who weighs 180 pounds and lifts weights four days a week will have a very different maintenance number than a 40-year-old woman who weighs 140 pounds and trains twice a week. Online TDEE calculators can give you a starting estimate using these inputs, but treat that number as a rough baseline. The real test is tracking your weight over two to three weeks while eating consistently. If your weight stays stable, you’ve found your maintenance level.
How Much to Add for Muscle Growth
Research published in the journal Sports Medicine recommends a surplus of 5 to 20% above your maintenance calories. If your TDEE is 2,500 calories, that means eating between 2,625 and 3,000 calories per day. The size of the surplus should scale to your experience level. Beginners can use the higher end of that range (closer to 20%) because their bodies are primed for rapid muscle adaptation. Intermediate and advanced lifters should stick to the lower end (5 to 10%) because their rate of muscle gain slows over time, and extra calories beyond what the body can use for growth simply get stored as fat.
A practical way to monitor this: aim for a weight gain of 0.25 to 0.5% of your body mass per week. For someone weighing 180 pounds, that’s roughly 0.5 to 0.9 pounds per week. If you’re gaining faster than that, you’re likely adding unnecessary fat. If you’re not gaining at all, bump your intake up by 100 to 200 calories and reassess after a couple of weeks.
Why Bigger Surpluses Don’t Build More Muscle
Your body can only synthesize a limited amount of muscle tissue in a given period. Most people can expect to gain about one to two pounds of lean muscle per month during their first year of serious training. After that initial phase, the rate drops to closer to half a pound per month. These are natural limits that no amount of extra food can override.
This is the core problem with “dirty bulking,” where people eat as much as possible to maximize growth. Once you’ve provided enough energy and protein for muscle repair, the excess gets stored as body fat. A study comparing small and large energy surpluses in trained lifters found a much stronger relationship between total weight gained and increases in skinfold thickness (a measure of fat) than between total weight gained and muscle. In other words, the bigger the surplus, the more of it becomes fat rather than muscle. A controlled approach gives you nearly the same muscle growth with far less fat to deal with later.
Protein: The Most Important Macro
Calories create the conditions for growth, but protein provides the raw material. A large meta-analysis found that muscle gains from resistance training plateau at a daily protein intake of about 1.6 grams per kilogram of body weight (0.73 grams per pound). The effective range extends up to 2.2 grams per kilogram (1 gram per pound) for those who want a margin of safety. For a 180-pound person, that works out to roughly 130 to 180 grams of protein per day.
Spreading protein across meals matters too. About 20 to 40 grams of high-quality protein per meal (roughly 0.3 grams per kilogram of body weight) is enough to maximally stimulate muscle protein synthesis. Eating 80 grams at dinner and skipping protein at breakfast is less effective than distributing it evenly across three or four meals.
Splitting the Rest: Carbs and Fats
After protein is set, the remaining calories come from carbohydrates and fats. Research on physique athletes suggests a split of roughly 55 to 60% of total calories from carbohydrates, 25 to 30% from protein, and 15 to 20% from fats. For someone eating 2,800 calories a day, that looks something like:
- Carbohydrates: 385 to 420 grams (fuels training intensity and replenishes muscle glycogen)
- Protein: 175 to 210 grams (supports muscle repair and growth)
- Fats: 47 to 62 grams (supports hormone production, including testosterone)
Carbohydrates deserve more attention than they often get in muscle-building diets. They’re your body’s preferred fuel for intense resistance training. When carb intake drops too low, training performance suffers, which limits the stimulus your muscles receive. Fats, meanwhile, should not drop below about 15% of total intake because they play a direct role in producing the hormones that drive muscle growth.
A Practical Example
Consider a 170-pound man in his late 20s who trains four days a week. His estimated TDEE is around 2,600 calories. As an intermediate lifter with about two years of consistent training, he’d aim for a surplus on the conservative side, around 10%. That puts his daily target at roughly 2,860 calories. His protein target would be about 150 grams per day (1.6 g/kg at his weight of 77 kg), split across four meals of around 35 to 40 grams each. The rest of his calories would come mostly from carbohydrates, with enough fat to stay in the 15 to 20% range.
He’d weigh himself daily, average the readings each week, and look for a gain of about 0.4 to 0.8 pounds per week. If progress stalls for two consecutive weeks, he’d add another 100 to 150 calories, primarily from carbohydrates. If his weight is climbing too fast, he’d trim the surplus slightly. This process of adjusting every few weeks is how you dial in the right number for your body, since calculators and formulas are only ever a starting point.
Special Situations
Building Muscle While Losing Fat
Complete beginners, people returning to training after a long break, and those carrying significant body fat can often build muscle in a calorie deficit. This is sometimes called body recomposition. It works because untrained muscles are extremely responsive to new training stimuli, and the body can redirect stored energy toward muscle repair. For everyone else, a surplus is necessary. Trying to stay lean while building muscle is possible, but it requires a very small, carefully managed surplus and patience.
Protecting Muscle During a Cut
If you’re in a calorie deficit to lose fat, protein needs actually go up, not down. Intakes of 2.3 to 3.1 grams per kilogram of lean body mass per day have been recommended to minimize muscle loss during weight loss phases. That’s significantly higher than the 1.6 g/kg recommendation during a surplus, because your body is more likely to break down muscle for energy when calories are restricted.