From calories to grams
Macronutrients are the three nutrients that provide energy: protein, carbohydrates and fat. Once you know your daily calorie target, a macro split tells you how many grams of each to eat. This calculator offers four common splits and a custom option, with amounts per day and per meal.
The formula
- Protein (g) = calories × protein share ÷ 4
- Carbohydrates (g) = calories × carb share ÷ 4
- Fat (g) = calories × fat share ÷ 9
Protein and carbohydrates provide 4 kcal per gram and fat 9 kcal per gram. In the custom option, fat takes whatever share remains after protein and carbs.
Worked example: 2,400 kcal, balanced
The balanced split is 20% protein, 50% carbohydrates and 30% fat.
- Protein: 2,400 × 0.20 ÷ 4 = 120 g.
- Carbs: 2,400 × 0.50 ÷ 4 = 300 g.
- Fat: 2,400 × 0.30 ÷ 9 = 80 g.
- Over three meals: 40 g of protein, 100 g of carbs and 27 g of fat per meal.
- Fiber to aim for: 34 g a day.
Balanced macros by calorie level
| Calories | Protein | Carbs | Fat |
|---|---|---|---|
| 1,600 | 80 g | 200 g | 53 g |
| 2,000 | 100 g | 250 g | 67 g |
| 2,400 | 120 g | 300 g | 80 g |
| 2,800 | 140 g | 350 g | 93 g |
| 3,200 | 160 g | 400 g | 107 g |
The four preset diets
- Balanced (20/50/30): close to the middle of US recommendations. A good default.
- High protein (30/40/30): helps keep muscle during weight loss and supports strength training.
- Low carb (30/20/50): fewer starches and sugars, more fat.
- Keto (20/5/75): very low carbohydrate, usually under 50 g a day, so the body switches to burning fat. It is restrictive and not suitable for everyone.
Recommended ranges
The Dietary Reference Intakes give acceptable ranges for adults: 10 to 35% of calories from protein, 45 to 65% from carbohydrates and 20 to 35% from fat. The Dietary Guidelines also advise keeping added sugars and saturated fat each under 10% of calories. Low-carb and keto splits fall outside these ranges by design.
Tips
- Start from calories. Use the calorie deficit calculator or the BMR calculator first; macros only split the total.
- Hit protein first. It is the macro most people fall short of when cutting calories.
- Track for a week or two. It shows where your diet stands. After that, many people can estimate by eye.
- Quality matters. The same grams of carbohydrate from beans and whole grains bring fiber and micronutrients that sugary drinks do not.
People with diabetes, kidney disease or other conditions should set their macros with a doctor or registered dietitian.