To determine your macros, you can use a macro calculator. There are several free online macro calculators available that can provide you with your optimal macronutrients and calories based on your age, physical characteristics, activity level, and bodyweight goals. These calculators can help you determine your daily targets for weight loss, weight gain, overall health and weight maintenance. By calculating the appropriate daily calorie amount for you, the calculator can then break this down into the best macronutrient ratios to achieve your goals. The macronutrients typically considered are carbohydrates, proteins, and fats. Once you have identified your target daily macros, you can determine the macros in all your foods by tracking them daily to reach your recommended macro targets that encourage fat loss, muscle gain, or whatever your goal may be.