Start with this calculation. Then once we have a total daily energy expenditure we can break down how many proteins/carbs/fats you need.
Your height in cm , your weight in kg , your age in years. Weigh yourself right before calculating - do not guesstimate!
For those in the US the conversions are as follows: 1 inch = 2.54 cm / 2.2 lbs = 1 kg
Calculate your BMR (basal metabolic rate):
Men: BMR = 66 + (13.7 x weight in kg) + (5 x height in cm) - (6.8 x age in years)
Women: BMR = 655 + (9.6 x weight in kg) + (1.8 x height in cm) - (4.7 x age in years)
Remember 1 inch = 2.54cm and 2.2 lbs = 1 kg.
Calculate your TDEE (total daily energy expenditure). This will tell you the average number of calories you burn based on your BMR and your daily activity level.
Sedentary = BMR X 1.2 (little or no exercise and a desk or still standing job)
Lightly active = BMR X 1.375 (light exercise or sports one to three times per week)
Moderately active = BMR X 1.55 (moderate exercise or sports three to five times per week)
Very active = BMR X 1.725 (hard exercise or sports six to seven times per week)
Extremely active = BMR X 1.9 (hard daily exercise or sports and a physical job, or twice a day training for an athletic event such as for a marathon or intense competition)
So the figure you come up with will be the average # of calories you burn daily. This number is crucial to us so we can adjust caloric intake in order to bulk (add mass) or cut (reduce body-fat) or even to maintain if that is your goal.
A few points - Remember this will only be as accurate as the data you put in as well as how honestly you assess your daily activity level. Be sure to be honest and accurate when calculating. There are other methods available to calculate your TDEE and while some will say they may be more accurate they also require data like bf%. Due to the difficultly in obtaining a truly accurate bf% reading - I say not only is the above method easier but also more accurate based on the ease by which accurate data can be obtained.