Macro calculator

How it works

Calories start from your TDEE, minus 550 a day to lose about 0.5 kg a week or plus 275 to gain about 0.25 kg. Protein is 1.8 g/kg (1.6 to maintain), capped at 35% of calories. Fat is 25% of calories, never below 0.5 g/kg. Carbs fill the rest.

How to read your result

The result is a daily calorie target plus grams of protein, carbs and fat. The calories are your estimated daily burn (TDEE), with a set amount added or taken off for your goal. Protein is set first, in grams per kilo of body weight. Fat comes next, as a share of calories. Carbs get whatever calories are left. If calories are low, protein is held to 35% of calories, the top of the 10 to 35% protein range in the US Dietary Guidelines. Fat is 25% of calories, inside that guide’s 20 to 35% range, and never drops below 0.5 g per kg.

Treat the result as a starting point, not a measurement. The calorie burn comes from the Mifflin-St Jeor equation. A review of the research found it predicted resting metabolic rate within 10% of the measured value in more people than the other common equations it compared. The same review also found noteworthy errors for individuals, and older adults and some ethnic minorities were underrepresented in the studies. Your activity level is your own choice, which adds more doubt. The goal step uses a simple rule of 7,700 kcal per kg of body fat. Real weight change is slower than a straight line: one model of adult metabolism found that bodyweight responds slowly to a change in intake, with half times of about 1 year.

Use it like this. Follow the numbers for a few weeks, watch your weight trend, and change the calories if it is not moving the way you want. The loss setting is 0.5 kg (about 1.1 lb) a week, which is inside the 1 to 2 pounds a week that the CDC describes as a gradual, steady pace. The gain setting is 0.25 kg (about 0.55 lb) a week. In the Zefro app you can pick other weekly rates. This page sets no minimum calorie level, so if the result looks very low for you, ask a doctor. If you are concerned about your weight or have questions about your medication, talk with your doctor too.

A worked example

Take a 30-year-old man, 80 kg (about 176 lb) and 180 cm (about 71 in), with moderate activity, who wants to lose fat. Step 1, BMR: 10 × 80 + 6.25 × 180 − 5 × 30 + 5 = 800 + 1,125 − 150 + 5 = 1,780 kcal. Step 2, TDEE: 1,780 × 1.55 = 2,759 kcal. Step 3, goal: 0.5 kg a week × 7,700 ÷ 7 days = 550 kcal a day, so 2,759 − 550 = 2,209 kcal. Step 4, protein: 1.8 × 80 = 144 g, which is 576 kcal. The 35% cap would allow 773 kcal, so it does not apply. Step 5, fat: 25% of 2,209 = 552 kcal. The floor is 0.5 × 80 × 9 = 360 kcal, so 552 stands: 552 ÷ 9 = 61 g. Step 6, carbs: 2,209 − 576 − 552 = 1,081 kcal, and 1,081 ÷ 4 = 270 g. Result: 2,209 kcal, 144 g protein, 270 g carbs, 61 g fat.

The same man with other goals. To maintain: 2,759 kcal, protein 1.6 × 80 = 128 g, fat 25% of 2,759 = 690 kcal = 77 g, carbs 389 g. To gain 0.25 kg a week: 2,759 + 275 = 3,034 kcal, protein 144 g, fat 84 g, carbs 425 g.