Macro Calculator: protein, carbs and fat per day

Find out how many grams of protein, carbohydrate and fat to eat a day for your calorie target, whether you want to lose fat, maintain or build muscle.

Macros per day
Macro	Per day	Per meal (3)	Share
Protein	137 g	46 g	20%
Carbohydrate	342 g	114 g	50%
Fat	91 g	30 g	30%

How it works

Your daily calories come from the calorie calculator's method (Mifflin–St Jeor BMR × activity), adjusted for your goal. Or tick “I know my calorie target” and type your own.
The split divides those calories between the three macros. Grams = calories × share ÷ 4 for protein and carbs, or ÷ 9 for fat.
Any share outside the recommended adult range is flagged, and your protein is shown per kg (or lb) of body weight.

Worked example

A 30-year-old man, 178 cm and 80 kg, exercising 3 to 5 days a week needs about 2,740 kcal a day to maintain his weight. With the balanced 50/20/30 split: carbohydrate 1,370 kcal ÷ 4 = 342 g, protein 548 kcal ÷ 4 = 137 g(1.71 g per kg), and fat 822 kcal ÷ 9 = 91 g a day.

The splits

Balanced: 50% carbohydrate, 20% protein, 30% fat.
Higher protein: 45% carbohydrate, 30% protein, 25% fat.
Lower fat: 60% carbohydrate, 20% protein, 20% fat.
Lower carb: 35% carbohydrate, 30% protein, 35% fat (below the usual carbohydrate range; fine for some people, but not a default).
Custom: type your own percentages; they must add up to 100.

Sources, checked 2 October 2026: Acceptable Macronutrient Distribution Ranges from the National Academies' Dietary Reference Intakes for macronutrients; protein advice from the Dietary Guidelines for Americans 2025–2030 (MedlinePlus summary); 4/4/9 kcal per gram from US FDA labelling rules (21 CFR 101.9). Not medical advice.

Frequently asked questions

What are macros?

Macronutrients are the three nutrients that provide calories: protein and carbohydrate (4 kcal per gram) and fat (9 kcal per gram). Alcohol also has calories (7 kcal per gram) but isn't a nutrient you need.

How much protein do I need a day?

The long-standing recommended amount for adults is 0.8 g per kg of body weight. The Dietary Guidelines for Americans 2025–2030 suggest 1.2 to 1.6 g per kg. People doing a lot of strength training often aim higher; ask a dietitian if you have kidney disease.

Which macro split should I choose?

For most adults, any split inside the recommended ranges (45–65% carbohydrate, 20–35% fat, 10–35% protein) can be healthy, so choose one you can stick to. For weight loss, total calories matter most; more protein can help you feel full and keep muscle.

Do I have to hit my macros exactly?

No. Aim to be roughly right over the week. Food labels and portion estimates aren't exact either, so a few grams either way don't matter.