Macro Calculator
Grams of protein, carbs and fat a day for your calories and eating style.
Good to know. A gram of fat has 9 kcal, more than twice a gram of carbs or protein. That’s why a little oil goes a long way.
Not medical advice. A general estimate for healthy adults.
How it works
In plain words
Split the calories by the percentages of your eating style, then divide by the energy in a gram: 4 kcal for protein and carbohydrates, 9 kcal for fat.
The formula
protein g = calories × protein % ÷ 4 carbs g = calories × carbs % ÷ 4 fat g = calories × fat % ÷ 9
Worked example
On 2,000 kcal with a balanced split: 20% protein is 400 kcal ÷ 4 = 100 g, 50% carbohydrates is 250 g, and 30% fat is 600 kcal ÷ 9 = 67 g.
Sources
- Institute of Medicine, Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids, 2005 Acceptable ranges: 45–65% carbohydrates, 10–35% protein, 20–35% fat; 0.8 g protein per kg.
Sources checked September 30, 2026. 3 automated tests check its answers on every change.
About the macro calculator
Macronutrients, or macros, are the three nutrients that provide energy: protein, carbohydrates and fat. Counting grams of each, rather than only calories, helps you eat enough protein to keep muscle, especially while losing weight, and balance the rest to your taste.
Start from a daily calorie target, for example from the calorie deficit or BMR calculator, and choose an eating style. The balanced split sits in the middle of the ranges the US National Academies recommend for adults: 45 to 65% of calories from carbohydrates, 10 to 35% from protein and 20 to 35% from fat. High-protein and low-carb splits shift energy toward protein and fat; keto keeps carbohydrates very low, usually under 50 g a day.
Protein needs are often easier to set per kilogram of body weight. The minimum for adults is 0.8 g per kg; people who train hard or are losing weight often aim for 1.2 to 2 g per kg. If the protein figure here is far from that for your weight, pick a different split.
Macros are a planning tool. Food labels and apps give grams per portion, so you can see how a day adds up. The quality of the food matters too: fibre, vitamins and minerals don’t show up in macro counts. If you have diabetes, kidney disease or another condition, ask a doctor or dietitian before changing your diet a lot.
Questions people ask
How do I calculate my macros?
Multiply your daily calories by each percentage, then divide by 4 for protein and carbohydrates and by 9 for fat. On 2,000 kcal at 20% protein: 400 ÷ 4 = 100 g.
How much protein do I need a day?
At least 0.8 g per kg of body weight for adults; 1.2 to 2 g per kg if you train hard or are losing weight.
What are keto macros?
Typically about 5% of calories from carbohydrates, 20 to 25% from protein and 70 to 75% from fat.