A macro counter takes the calorie target a TDEE and deficit calculation gives you and splits it into protein, carbohydrate and fat. Counting macros matters because the three are not interchangeable: protein drives muscle retention and satiety, so hitting a protein target is the part of macro counting that changes results most, whatever the rest of the split looks like.
What macros are and why they matter
Macros, short for macronutrients, are protein, carbohydrate and fat, the three sources of calories. What are macros in practice is a way of spending a calorie budget: the same total can be split many ways, and counting macros rather than just calories lets you protect muscle with enough protein and fuel training with enough carbohydrate, which a bare calorie count ignores.
Setting the split
A bodybuilding macro calculator, or any macro calculator free of jargon, starts with protein set from bodyweight, adds enough fat for health and satiety, and fills the rest with carbohydrate. Protein is the anchor because it is the macro that most protects muscle in a deficit and drives fullness; the carbohydrate-to-fat balance beyond that is largely preference and training demand.
Counting alcohol
Alcohol is a fourth source of calories that a full macro counter has to account for, which is why people ask how to track alcohol macros. Alcohol carries calories but no useful macro role, so the honest way to track alcohol macros is to log its calories against the day's total, usually against the fat or carbohydrate budget, and accept that it displaces food rather than adding to it.
Questions people ask about macro counter
What are macros?
Macros are the three calorie sources, protein, carbohydrate and fat; counting them splits a calorie target so you protect muscle with protein and fuel training with carbohydrate rather than tracking calories alone.
What is the most important macro?
Protein, because it most protects muscle in a deficit and drives satiety; set it from bodyweight first and let the carbohydrate-to-fat balance follow preference and training.
How do you track alcohol macros?
Alcohol carries calories but no useful macro role, so log its calories against the day's total, usually against fat or carbohydrate, and treat it as displacing food rather than adding to it.