Macro Calculator
Enter your daily calorie target and pick a diet style — the grams update as you type. This is a general estimate, not personalized medical or nutrition advice.
How this calculator works
Every diet style here is just a different way of dividing the same calorie budget among protein, carbohydrate, and fat. We convert each macronutrient's calorie share into grams using the Atwater factors — the standard energy values of 4 kcal per gram for protein and carbs, and 9 kcal per gram for fat. Pick a preset for common, roughly-consistent splits, or switch to custom percentages if you have specific numbers in mind — just make sure your three percentages add up to 100%; we won't silently adjust them for you. This is a general estimate, not medical or nutrition advice.
Worked example
A 2,200-calorie target on the Balanced preset (30% protein / 40% carb / 30% fat) splits as: protein calories 2,200 × 30% = 660, so 660 ÷ 4 = 165 g protein; carb calories 2,200 × 40% = 880, so 880 ÷ 4 = 220 g carbs; and fat calories 2,200 × 30% = 660, so 660 ÷ 9 ≈ 73.3 g fat. Those three gram amounts, at 4/4/9 kcal per gram, add back up to the original 2,200 calories.
Frequently asked questions
Why is protein 4 calories per gram but fat is 9?
These are the Atwater factors, the long-standing nutrition-science averages for how much usable energy each macronutrient yields when the body metabolizes it: about 4 kcal per gram of protein, 4 kcal per gram of carbohydrate, and 9 kcal per gram of fat. Fat packs more than double the energy per gram, which is why a small shift in fat percentage moves fewer grams than the same shift in protein or carbs.
Which diet style is "best"?
There's no universal best split — it depends on your goals, preferences, training, and any medical situation, and this tool can't give you personalized advice. The presets here are common, roughly-consistent starting points, not prescriptions. If you want help setting the calorie target this tool splits, our calorie-calculator estimates daily needs, and the protein-intake-calculator gives a research-informed protein range you can build the rest of your macros around.
Do I need to hit these gram targets exactly every day?
No. Day-to-day totals bounce around with restaurant meals, portion estimates, and normal appetite changes — what matters more is your average over a week or two. Treat these numbers as a target to land near most days, not a bar you fail by missing on any single day.
What about fiber, vitamins, and other micronutrients?
This tool only splits calories into protein, carbohydrate, and fat grams — it doesn't track fiber, vitamins, minerals, or other micronutrients, and it isn't trying to. Those matter for overall health, but they're outside what a macro split can tell you.
Is this medical or nutrition advice?
No. This calculator produces a general estimate based on simple arithmetic and commonly-cited macronutrient ranges — it is not medical or nutrition advice tailored to you. Talk to a doctor or registered dietitian before making significant changes to your diet, especially if you have a medical condition.