Macro Calculator
Split a daily calorie target into protein, carbohydrate, and fat grams by a chosen ratio.
Split adds up to 100% · Balanced.
To split calories into macros, multiply the calorie target by each macro’s percentage, then divide by its energy density: 4 kcal/g for carbs and protein, 9 kcal/g for fat. At 2,000 kcal on a 40/30/30 carb/protein/fat split that gives 200 g carbs, 150 g protein, and about 67 g fat.
What a macro split does
Your macronutrients — carbohydrate, protein, and fat — are the three nutrients that supply energy. A macro calculator takes a daily calorie target and a percentage split, then converts each slice of calories into grams you can actually track on a food label. The split you choose changes the grams but not the total calories: the three percentages always add up to 100%.
The conversion hinges on energy density. Carbohydrate and protein each provide about 4 kcal per gram, while fat provides about 9 kcal per gram — more than twice as much. That is why the same share of calories yields far fewer grams of fat than of carbs or protein.
Carbohydrate and protein supply 4 kcal/g; fat supplies 9 kcal/g.
Worked example: 2,000 kcal at 40/30/30 (carb/protein/fat)
Take each macro’s share of the 2,000 kcal, then divide by its energy density:
- 1 Set your calorie target. Start from a maintenance or goal figure — for example 2,000 kcal/day.
- 2 Choose a percentage split. Pick carb/protein/fat percentages that add up to 100%, such as 40/30/30.
- 3 Carbohydrate grams. 2,000 × 40% = 800 kcal; 800 ÷ 4 = 200 g of carbohydrate.
- 4 Protein grams. 2,000 × 30% = 600 kcal; 600 ÷ 4 = 150 g of protein.
- 5 Fat grams. 2,000 × 30% = 600 kcal; 600 ÷ 9 ≈ 66.7 g, about 67 g of fat.
Common macro ratios (carb / protein / fat)
Grams shown for a 2,000 kcal/day target. Carbs and protein at 4 kcal/g, fat at 9 kcal/g.
| Ratio | Carb / Protein / Fat | Carbs | Protein | Fat |
|---|---|---|---|---|
| Balanced | 40 / 30 / 30 | 200 g | 150 g | 67 g |
| High-protein | 40 / 40 / 20 | 200 g | 200 g | 44 g |
| Low-carb | 25 / 40 / 35 | 125 g | 200 g | 78 g |
| Keto | 5 / 25 / 70 | 25 g | 125 g | 156 g |
Choosing and using a split
No single ratio is best for everyone. A balanced split suits general eating, high-protein supports muscle retention while dieting, low-carb and keto shift energy toward fat. Protein needs are often set first — many people aim for roughly 1.6–2.2 g of protein per kilogram of body weight — with carbs and fat filling the rest. Round grams to the nearest whole number; small rounding differences in the fat line are normal because 9 does not divide calories evenly.
This tool is an informational estimate, not medical or dietary advice. Individual needs vary — consult a qualified dietitian or doctor before making significant dietary changes.