If you’ve just started a new strength-training routine and are trying to build muscle mass, you may be wondering how many calories you should be eating to meet your body composition goals.
To build muscle, you need to consume the right number of calories along with a balanced mix of macronutrients to fuel growth without leading to excess fat gain, which can be tricky.
To help clarify the confusion, we asked experts to explain how many calories are needed for muscle growth.
To give your body the energy it needs to repair and build muscle, you need a modest calorie surplus. “The body requires additional energy to build new muscle tissue while minimizing excess fat gain,” Trista Best, MPH, RD, told Health. Eating too little reduces energy availability and may impact hormones, making it harder to build muscle.
That said, eating too large a calorie surplus doesn’t necessarily lead to greater muscle gains. In a 2023 study, resistance-trained participants who consumed higher calorie surpluses gained similar strength and muscle size as those eating smaller calorie surpluses, but also accumulated more body fat.
These findings indicate that the most effective way to support muscle growth while minimizing fat gain is to maintain a more conservative calorie surplus, about 5–20% above your maintenance calories. For someone who normally consumes 2,000 calories a day, this translates to a surplus of between 100 and 400 calories.
A smaller calorie surplus may be recommended for a person who’s looking to drop body fat while gaining muscle, while a larger energy surplus may be needed for someone who’s highly active and has little body fat, such as an athlete.
“Your calorie needs depend on factors such as your Basal Metabolic Rate (BMR), activity level, age, gender, weight, and training experience,” sports dietitian Alex Larsen, MS, RDN, told Health.
Basal Metabolic Rate (BMR)
Basal Metabolic Rate (BMR) is the number of calories your body burns at rest to sustain essential functions, like breathing, circulation, and cell repair.
Your BMR accounts for 60 to 70% of your daily energy expenditure and is influenced by your age, gender, genetics, and body composition.
Total Daily Energy Expenditure (TDEE)
TDEE is the total number of calories your body burns in a day. It includes your BMR, the calories used to digest and process food (thermic effect of food, or TEF), and the energy spent during physical activity.
TEF accounts for about 10% of your daily calories. Protein has the highest TEF (20–30%), followed by carbs (5–10%) and fats (0–3%), meaning higher-protein diets can slightly boost calorie burn.
Age, Gender, and Weight
Your age, gender, and weight impact how many calories you need.
Generally, younger people, men, and those with more muscle mass burn more calories, while older adults, women, and people with more body fat burn fewer calories.
Activity Level
People who only workout occasionally will require fewer calories than avid gym-goers and those that lead generally active lifestyles.
The more active you are, the more calories you’ll need to maintain your body weight or gain muscle mass.
Before you can determine how many more calories you need to eat for muscle growth, you’ll need to determine your daily calorie needs.
While the most precise method involves clinical tests like direct or indirect calorimetry, most people don’t have access to this equipment. Thankfully, you can use formulas like the Mifflin-St. Jeor equation, which factors in your age, weight, height, and activity level, to calculate your estimated daily calorie needs.
The Mifflin-St. Jeor Equation
You’ll plug in your height, weight, and age into the following formulas to determine your calorie needs.
Here are the equations for men and women:
- Men: calories per day = 9.99 (weight in kilograms (kg)) + 6.25 (height in centimeters (cm)) –4.92 (age) + 5
- Women: calories per day = 9.99 (weight in kg) + 6.25 (height in cm) – 4.92 (age) – 161
Once you calculate this number, multiply it by an activity factor to account for your daily movement:
- Sedentary: x 1.2 (sedentary)
- Lightly active: x 1.375 (light exercise less than three days per week)
- Moderately active: x 1.55 (moderate exercise most days of the week)
- Very active: x 1.725 (hard exercise every day)
- Extra active: x 1.9 (strenuous exercise two or more times per day)
This gives you an estimate of your TDEE. From there, you can add a 5–20% calorie surplus, depending on your muscle-gain goals, body composition targets, and training program.
When it comes to building muscle, your macronutrient intake matters. Protein is the most important macronutrient for building muscle, supplying the amino acids your body needs to repair and grow muscle tissue.
While the general RDA is 0.8 grams per kilogram of body weight, research shows that those aiming to build muscle benefit from higher intakes. Most studies suggest consuming 1.6 to 3.1 grams per kilogram (0.7 to 1.4 grams per pound) of protein daily, paired with resistance training, to maximize muscle growth. This equates to roughly 105–210 grams per day for someone weighing 150 pounds.
Though less important than protein, carbs and fats should be included in any well-rounded diet. While there’s no specific range for muscle building, generally speaking, carbs and fats should make up 45–65% and 20–35% of your daily calorie intake, respectively.
If you want to reach your muscle gain goals while losing or maintaining your body fat, follow these tips:
- Start small: Start on the low end of the recommended 5–20% calorie surplus and increase your calories only if needed.
- Prioritize whole foods: Focus on nutrient-dense foods rich in protein and fiber, which naturally help curb your appetite.
- Eat a high-protein diet: Add protein-rich foods to each meal and snack to ensure you’re meeting your protein needs.
- Stay consistent: Muscle gain can be a slow process, which is why it’s important to stay consistent with dietary changes and your workout routine.
- Monitor your progress: Though not necessary, monitoring your progress using photos or body measurements can help show you that you’re on the right track.
While strength-training is key to building muscle, you also need to fuel your body with enough calories and the right balance of macros.
Studies show that a calorie surplus between 5–20% can help you build muscle while engaging in a consistent strength-training routine.
However, your exact calorie needs depend on factors like your age, activity level, weight, and training level.
