How do I calculate macros? Calculating how many grams of each macro you consume daily is specific to your goals and several other factors.
First, you must determine your maintenance calorie needs. There are several online calculators which makes this easy. Here’s one: http://www.freedieting.com/tools/calorie_calculator.htm
Then, you will use your maintenance calorie level as your baseline. If your goal is to lose weight, then you will subtract a couple hundred calories (up to 500) or add a couple hundred if your goal is to gain weight. If your goal is neither losing or gaining weight, and you just want to change your body composition (lose fat and increase muscle) then you can keep your calories at your baseline.
From there, you can use this calculator (http://macronutrientcalculator.com) to distribute your macros. Several factors come in to play when choosing which split or breakdown you use. Depending on your body type, age, gender, goals, and intensity of your weight training will determine which is best suited for you to use. The best general guidelines that seem to work well for beginners is the moderate (50% carb, 30% protein, 20% fat) and zone (40% carb, 30% protein, 30% fat) tabs. Each split will tell you how many grams of each macro to consume daily to meet your calorie needs.
Finally, it’s important to remember that not all calories and macronutrients are created equal. Be sure to include a lot of nutritious foods that will ensure you are also meeting your micronutrient (vitamin and mineral) needs as well. Fruits, vegetables, legumes, nuts and seeds, whole grains, and eggs are great micronutrient-dense sources of macronutrients.