How do I calculate my macros?

Start with your daily calorie target, pick a protein/carb/fat split, then convert percentages to grams: protein and carbs carry 4 calories per gram, fat carries 9. For example, 30% protein on 2,000 calories is 600 kcal ÷ 4 = 150 g of protein per day. This calculator does that arithmetic for four common diet styles.

How many calories should I enter into a macro calculator?

Your maintenance calories (TDEE), adjusted for your goal — subtract roughly 250–500 kcal to lose fat, add 250–500 to build muscle. If you don't know your TDEE, calculate it first with our TDEE calculator; macros computed from a guessed calorie number are precisely-measured nonsense.

How much protein should I eat per day?

The evidence-based range for active people is about 0.7–1.0 g per pound of body weight (1.6–2.2 g/kg) per day. Above that isn't harmful for healthy people, but returns diminish quickly. People dieting hard should aim at the top of the range to protect muscle; sedentary people can do fine on somewhat less.

Do I have to hit my macros exactly?

No — landing within 5–10 g of each target is effectively perfect. Prioritize the weekly average over any single day, and prioritize protein and total calories over the exact carb/fat split. Months of 90% consistency beat weeks of 100% precision every time.

Which macro split is best for weight loss?

The one you can stick to. Controlled studies comparing low-carb and low-fat diets at matched calories and matched protein find nearly identical fat loss. Calories determine whether weight changes, protein determines how much of the loss is muscle, and the carb/fat split is mostly personal preference and food culture.

Macro Calculator — Protein, Carb & Fat Grams Per Day

Enter your daily calorie target and pick a diet style to get your macros — grams of protein, carbohydrate, and fat per day. Add your body weight to check the protein target against the evidence-based range.

How the macro calculator works

Your calorie target decides whether your weight goes up or down; your macros decide what that change is made of. This calculator takes the calorie number you give it (it does not second-guess your goal — the goal selector just annotates the result) and carves it into protein, carbohydrate, and fat using the split you pick. Protein is the anchor: it protects muscle in a deficit and builds it in a surplus, which is why every preset here keeps protein at 30% or higher. Fat is set next — hormones and vitamin absorption want a floor under it — and carbohydrate fills whatever calories remain.

The formula

grams of protein = calories × protein % ÷ 4 • grams of carbs = calories × carb % ÷ 4 • grams of fat = calories × fat % ÷ 9

The divisors are the Atwater factors: protein and carbohydrate each supply about 4 kcal per gram, fat supplies 9 — more than twice the energy density, which is why fat grams always look small next to their calorie share. One bookkeeping detail: after rounding protein and fat to whole grams, this calculator hands every leftover calorie to carbs, so the three calorie columns always sum exactly to your target instead of drifting a few kcal from rounding.

Worked example

A 2,000 kcal target on the Balanced 30P / 40C / 30F split, body weight 165 lbs:

Protein: 2,000 × 0.30 = 600 kcal ÷ 4 = 150 g

Fat: 2,000 × 0.30 = 600 kcal ÷ 9 = 66.7 → 67 g (603 kcal)

Carbs get the remainder: 2,000 − 600 − 603 = 797 kcal ÷ 4 ≈ 199 g

Protein check: 150 g ÷ 165 lbs = 0.91 g per pound — comfortably inside the 0.7–1.0 g/lb evidence range.

Protein anchors the plan

If you remember one number from this page, make it the protein target. Meta-analyses of resistance-training studies converge on roughly 0.7–1.0 g of protein per pound of body weight (1.6–2.2 g/kg) per day as the range where muscle retention and growth are maximized; more than that is mostly expensive urine for healthy people. Enter your body weight above and the calculator grades your split against that range automatically. If the check comes back low, the fix is usually to switch to the high-protein preset or to raise total calories — not to obsess over the carb/fat ratio, which study after study finds barely matters for body composition once calories and protein are matched.

Consistency beats precision (and eat your fiber)

Macro tracking fails in two directions: people who quit because 172 g of carbs felt impossibly fussy, and people who hit 172.0 g daily for six weeks and then burn out spectacularly. Both miss the point — these targets are weekly averages wearing daily clothes. Within 5–10 g of each macro is a bullseye, and one rogue Tuesday changes nothing. While you're tracking, watch one non-macro number: fiber. Aim for about 14 g per 1,000 kcal (roughly 28 g on our example's 2,000), which mostly takes care of itself if your carbs lean toward plants rather than powders. Low-carb and keto dieters have to work hardest at this — at 5% carbs, every gram should probably be a vegetable.

Macro Calculator