Estimating your recommended caloric intake for weight gain is straightforward, but for best effects you will need to monitor your actual caloric intake and your weight to fine tune these estimates. Use a TDEE calculator to estimate the number of calories you burn in an average day. Your TDEE is also known as your "maintenance" calories. Use a macro calculator to determine how many calories you should consume for weight gain and what their macro split should be (protein, carbs, and fats). Generally speaking, an extra 300 calories per day is recommended for a "slow bulk" of approximately one extra pound every two weeks.