Macro
calculator.
Turn a daily calorie target into grams of protein, carbohydrate and fat. Start from a split that stays inside the adult Acceptable Macronutrient Distribution Ranges, type your own percentages, or set protein by body weight, and see every gram per meal.
2,000 kcal split 20/50/30 (protein/carbohydrate/fat) is 100 g of protein, 250 g of carbohydrate and 67 g of fat a day (33 g, 83 g and 22 g at each of 3 meals).
- Protein
- 100 g · 400 kcal · 20%
- Carbohydrate
- 250 g · 1,000 kcal · 50%
- Fat
- 67 g · 600 kcal · 30%
- Protein per kg of body weight
- 1.43 g/kg (RDA for adults: 0.8)
- Saturated fat under 10% of calories
- under 22 g
- Fiber at 14 g per 1,000 kcal
- 28 g
protein = 2,000 × 20% ÷ 4 = 100 g; carbohydrate = 2,000 × 50% ÷ 4 = 250 g; fat = 2,000 × 30% ÷ 9 = 66.67 gCalories in,
grams out.
- Grams = daily calories × share of calories ÷ energy per gram: 4 kcal/g for protein and carbohydrate, 9 kcal/g for fat (the general Atwater factors used on U.S. nutrition labels).
- Adult Acceptable Macronutrient Distribution Ranges (Dietary Reference Intakes): protein 10–35%, carbohydrate 45–65%, fat 20–35% of calories. Every preset sits inside all three; any share outside is flagged.
- Your own split must add up to exactly 100%. With protein by weight, protein = kg × g/kg × 4 kcal, fat is a share of calories, and carbohydrate gets the calories left over.
- Reference lines: saturated fat under 10% of calories (Dietary Guidelines 2025–2030) and fiber at 14 g per 1,000 kcal, the ratio behind the DRI Adequate Intake.
- Nothing is rounded until display. Grams are shown to the nearest gram, so they can total up to 9 kcal more or less than the target.
How do you calculate macros from calories?
Multiply your calories by each macronutrient’s share to get its calories, then divide by its energy per gram. For 2,000 kcal split 20/50/30: protein 2,000 × 20% = 400 kcal ÷ 4 = 100 g; carbohydrate 2,000 × 50% = 1,000 kcal ÷ 4 = 250 g; fat 2,000 × 30% = 600 kcal ÷ 9 = 67 g. Over three meals that is about 33 g, 83 g and 22 g a meal.
grams = calories × share ÷ kcal per gram
protein 4, carbohydrate 4, fat 9 kcal/gWhat are the recommended macro percentages?
The Dietary Reference Intakes set Acceptable Macronutrient Distribution Ranges for adults: 45–65% of calories from carbohydrate, 20–35% from fat and 10–35% from protein. The National Academies describe the ranges as flexible for planning, because the three can substitute for one another to some extent. Any split inside all three is consistent with the ranges; the presets here are four examples, such as 30/45/25 for more protein, which at 2,500 kcal gives 187.5 g of protein, 281.25 g of carbohydrate and 69.4 g of fat.
Is a 30/40/30 or low-carb split inside the ranges?
No. A 30/40/30 split puts carbohydrate at 40%, below the 45% floor, so the calculator flags it. At 1,800 kcal it is 135 g of protein, 180 g of carbohydrate and 60 g of fat. Lower-carbohydrate patterns are outside the adult ranges by design; the 2025–2030 Dietary Guidelines say people with certain chronic diseases may do better on a lower-carbohydrate diet and should choose one with their health care professional.
How do you set macros with protein per kilogram?
Fix protein first from body weight, set fat as a share, and give carbohydrate whatever is left. An 80 kg person at 1.8 g/kg eats 144 g of protein (576 kcal). At 2,600 kcal with 30% fat (780 kcal = 86.7 g), carbohydrate gets 2,600 − 576 − 780 = 1,244 kcal = 311 g, or 47.8% of calories. Protein is 22.2%, inside the range. The protein calculator compares g/kg references.
How many calories are in a gram of protein, carbs and fat?
4 kcal per gram of protein, 4 per gram of carbohydrate and 9 per gram of fat. These general Atwater factors, 17, 17 and 37 kJ/g, are the ones FDA nutrition labeling allows and FAO describes. They are averages: real foods differ slightly, and the same rule lets labels count soluble non-digestible carbohydrate at 2 kcal/g. So 67 g of fat is about 600 kcal and 250 g of carbohydrate is about 1,000 kcal.
Worked examples.
Balanced split
2,000 kcal, Balanced 20/50/30, three meals, 70 kg.
100 g protein · 250 g carbs · 67 g fat; 33, 83 and 22 g a meal.
Load this exampleHigher protein
2,500 kcal, Higher protein 30/45/25, four meals.
188 g protein · 281 g carbs · 69 g fat.
Load this exampleA 30/40/30 split
1,800 kcal with your own 30% protein, 40% carbohydrate, 30% fat.
135 g protein · 180 g carbs · 60 g fat; carbohydrate at 40% is below the 45–65% range.
Load this exampleProtein by body weight
80 kg at 1.8 g/kg protein, 30% fat, 2,600 kcal, four meals.
144 g protein · 311 g carbs · 87 g fat; carbohydrate is 47.8%.
Load this exampleEndurance training day
3,000 kcal, Higher carb 15/65/20, five meals.
113 g protein · 488 g carbs · 67 g fat.
Load this exampleHigh protein in pounds
180 lb at 2.2 g/kg protein, 25% fat, 2,200 kcal, three meals.
180 g protein · 233 g carbs · 61 g fat; carbohydrate at 42.3% is below the range.
Load this exampleWhat this calculator
does not do.
- It splits a calorie target you supply; it does not estimate your calorie needs. Use a calorie (TDEE) estimate or a figure from your dietitian.
- The ranges and presets are for adults. Children aged 1–3 and 4–18 have different ranges.
- 4, 4 and 9 kcal per gram are general averages. Labels round, and fiber, sugar alcohols and alcohol (7 kcal/g) are not counted separately.
- It is arithmetic for meal planning, informational only and not medical or dietary advice. Anyone with diabetes, kidney disease or another condition should plan with a clinician or dietitian.
Common questions.
How do I convert calories to grams of protein, carbs and fat?
Multiply calories by each share, then divide by 4 for protein and carbohydrate and by 9 for fat. 2,000 kcal at 20/50/30 is 100 g, 250 g and 67 g.
What is a good macro ratio?
Any split inside the adult ranges, protein 10–35%, carbohydrate 45–65% and fat 20–35% of calories, is consistent with the Dietary Reference Intakes. Which one suits you depends on your food preferences, training and health.
Why don’t my grams add up exactly to my calories?
Grams are rounded to the nearest gram for display. Each rounding moves the total by at most 2 kcal for protein or carbohydrate and 4.5 kcal for fat, up to 9 kcal in all.
What does AMDR mean?
Acceptable Macronutrient Distribution Range: the range of shares of calories from protein, carbohydrate and fat that the Dietary Reference Intakes give for adults (10–35%, 45–65% and 20–35%). Children have their own ranges.
Can I enter protein in grams per kilogram?
Yes. Choose “Protein by weight”, enter your weight and g/kg, and the fat share. Carbohydrate takes the remaining calories, and the calculator flags any share outside the ranges.
- National Academies: report on energy and macronutrients (2002) — adults: 45–65% of calories from carbohydrate, 20–35% from fat, 10–35% from protein; ranges flexible because macronutrients can substitute for one another
- Health Canada: Dietary Reference Intakes tables, reference values for macronutrients — AMDR by age (1–3, 4–18, 19 and over); total fibre AI based on 14 g per 1,000 kcal
- 21 CFR 101.9(c)(1)(i), nutrition labeling of food — general factors of 4, 4 and 9 calories per gram for protein, total carbohydrate and total fat
- FAO: Food energy, methods of analysis and conversion factors (Food and Nutrition Paper 77), chapter 3 — Atwater general factors: 17 kJ/g (4.0 kcal/g) protein and carbohydrate, 37 kJ/g (9.0 kcal/g) fat, 29 kJ/g (7.0 kcal/g) alcohol
- USDA and HHS: Dietary Guidelines for Americans, 2025–2030 — saturated fat should not exceed 10% of total daily calories; lower-carbohydrate diets for some chronic diseases with a health care professional
Each macro’s calories are the calorie target times its share, and grams divide by 4, 4 or 9. With protein by weight, carbohydrate is the remainder. Nothing is rounded before display. Our tests check six hand-worked cases, confirm that every preset sits inside all three adult ranges, run 400 seeded random splits to confirm the grams always rebuild the calorie target and the shares always total 100%, check that the kg and lb entries agree, and validate every field, including shares that do not add up and protein plus fat that exceed the calories.
Built and reviewed by CalculatorLab against the sources above; every worked example on this page is re-checked by our automated test suite before each release. How we build and check calculators. Found a problem? Tell us.