How macros are worked out
The calculator first finds your calorie target, then splits it into the three macronutrients. Calories come from your basal metabolic rate (Mifflin-St Jeor), scaled by activity and adjusted for your goal:
Calories = BMR × activity ± goal adjustment
Each macro's grams come from its share of those calories, divided by its calorie density — 4 cal/g for protein and carbs, 9 cal/g for fat:
Protein g = calories × protein% ÷ 4 | Fat g = calories × fat% ÷ 9
Choosing a split
- Balanced (30/40/30): a solid default for general health and fitness.
- High protein (40/40/20): protects muscle when cutting and aids satiety.
- Low carb (40/20/40): for those who feel better on fewer carbs.
- Keto (25/5/70): very low carb, high fat.
Hit protein and calories first
If tracking all three macros feels like a lot, prioritize your protein target and your total calories — those drive most of the results. Carbs and fat can flex around your preferences as long as the totals hold.
Frequently asked questions
How are macros calculated?
First the calculator finds your daily calories: it estimates your basal metabolic rate with the Mifflin-St Jeor equation, multiplies by an activity factor for your total daily energy expenditure, then adjusts for your goal. Those calories are split into protein, carbs, and fat using your chosen ratio — protein and carbs provide 4 calories per gram, fat provides 9.
What is a good macro split?
A balanced 30% protein, 40% carb, 30% fat split suits most people. Higher protein (40/40/20) supports muscle retention while losing fat; lower carb (40/20/40) and keto (25/5/70) suit different preferences. There is no single best split — consistency and total calories matter most.
How much protein do I need?
A common range is 0.7 to 1 gram of protein per pound of body weight, especially when training or in a calorie deficit. The percentage-based split here gives a solid starting point; if you are very active, lean toward the higher-protein options.
Should I eat the same macros every day?
Daily targets are a guide, not a rule. Hitting your protein goal and staying near your calorie target most days matters far more than perfect daily macros. Adjust after a few weeks based on how your weight and energy actually respond.
Disclaimer: These are estimates for general fitness planning, not medical or dietary advice. Consult a professional before making significant changes, especially with a health condition.