Bulking requires consuming more calories than your body needs.

You can estimate your daily calorie needs by using a calorie counter, which considers your weight, sex, age, height, and physical activity level to estimate your daily calorie needs.

Experts recommend consuming 10–20% above your daily weight maintenance calorie needs during the bulking phase for an average weight gain of 0.25–0.5% of your body weight per week.

For example, if you need 3,000 daily calories per day to maintain weight, you should aim to consume 3,300–3,600 instead, depending on your experience level. For a person who weighs 150 pounds (68 kg), this equates to an increase of 0.4–0.8 pounds (0.2–0.4 kg) per week.

While novice bodybuilders who have 6 months or less of weight training experience should aim for the higher end of this calorie range, bodybuilders with several years of experience should target the lower end to limit increases in body fat.

If you’re gaining less or more than 0.25–0.5% of your body weight per week, you should adjust your calorie intake accordingly.

Macronutrients
Once you establish the number of calories you need for bulking, you can determine your macronutrient ratios.

Macronutrients carbs, fats, and proteins are the nutrients that are needed in larger quantities in your diet. Carbs and protein each contain 4 calories per gram, while fat packs 9.

Experts recommend that you get:

45–60% of your calories from carbs
30–35% of your calories from protein
15–30% of your calories from fat
For example, if you decide you need to eat 3,300 calories per day, your diet would contain:

371–495 grams of carbs
248–289 grams of protein
55–110 grams of fat
While you can make adjustments based on your dietary needs, the proportion of calories from protein should remain at 30–35% to support optimal muscle growth.

You can use calorie tracking apps to help you stay within your calorie budget and macronutrient ranges.

Bodybuilding consists of three main phases bulking, cutting, and maintenance. Generally, bulking is meant to increase muscle mass and strength, whereas cutting is intended to shed excess body fat while maintaining muscle mass.