Macro calculator
Macro calculator: protein, fat and carbs.
EstimateDaily calories
Estimate. The fat and carb splits are Calowly's default presets, not a clinical standard.
It turns your TDEE into a daily calorie target with protein, fat and carbs in grams for losing, maintaining or gaining weight.
Track this target in Calowly.
Set your calorie target in the app and snap your meals. Calo shows how each one fits your day, so the number on this page turns into what you actually eat.
How it works
First the calculator estimates your TDEE with the Mifflin-St Jeor equation and your activity level, then sets calories for your goal and splits them into protein, fat and carbs:
Men: BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5
Women: BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age − 161
TDEE = BMR × activity factor (1.2 to 1.9)
Calories = TDEE − 550 (lose), TDEE (maintain) or TDEE + 250 (gain)
Protein (g) = body weight in kg × 1.6 / 1.4 / 1.8
Fat (g) = calories × 30% / 40% / 20% ÷ 9
Carbs (g) = (calories − protein × 4 − fat calories) ÷ 4
Losing uses 550 kcal a day below your TDEE, about 0.5 kg a week, and never goes below 1,200 kcal for women or 1,500 for men. Protein is set per kilogram of body weight: 1.6 g to lose, 1.4 g to maintain and 1.8 g to gain. Fat is a share of calories (30% balanced, 40% lower carb, 20% higher carb), and carbs fill the rest at 4 kcal per gram.
These fat and carb splits are Calowly's default presets, not a clinical standard. Any split that fits your calories and protein can work, so pick the one you can stick with.
Example: a 30-year-old man (80 kg, 180 cm, moderately active) who wants to keep his weight with the balanced split eats about 2,759 kcal a day: 112 g protein, 92 g fat and 371 g carbs.
Goals and splits
Calowly's default presets, not a clinical standard.
| Lose | TDEE − 550 kcal | 1.6 g protein per kg |
|---|---|---|
| Maintain | TDEE | 1.4 g protein per kg |
| Gain | TDEE + 250 kcal | 1.8 g protein per kg |
| Balanced | Fat share of calories | 30% |
| Lower carb | Fat share of calories | 40% |
| Higher carb | Fat share of calories | 20% |
Activity levels
| Sedentary | desk job, little or no exercise | × 1.2 |
|---|---|---|
| Lightly active | light exercise 1-3 days a week | × 1.375 |
| Moderately active | moderate exercise 3-5 days a week | × 1.55 |
| Very active | hard exercise 6-7 days a week | × 1.725 |
| Extremely active | physical job plus hard training most days | × 1.9 |
Common questions
What are macros?
Macros, short for macronutrients, are the three nutrients that supply calories: protein and carbohydrate with about 4 kcal per gram, and fat with about 9. Counting them on top of calories helps you eat enough protein and shape the rest of your diet around the foods you prefer.
Which macro split is best for weight loss?
For weight loss, total calories and enough protein matter most. The balanced, lower-carb and higher-carb options here are Calowly's defaults, not a clinical standard, and each keeps protein the same. Choose the split that suits your appetite and food choices, because the one you can keep up works best.
Why is protein higher when losing or gaining weight?
When you eat less, more protein helps you hold on to muscle, so the calculator uses 1.6 g per kg to lose. When you gain, it supports building muscle with 1.8 g per kg. Maintaining uses 1.4 g per kg. All three sit within the ranges discussed in the sources below.
What if the calculator shows no carbs?
If protein and fat already use up your calories, nothing is left for carbs. That can happen with a high body weight and a low calorie target. Try the balanced or higher-carb option, or a gentler goal. If you have a lot of weight to lose, advice from a doctor or dietitian is worth getting.
Do I have to hit my macros exactly?
No. Treat the grams as daily targets and aim to land close over the week. Getting calories and protein roughly right matters more than matching fat and carbs to the gram. Logging meals in an app makes it much easier to see where you stand during the day.
Related calculators
Calorie database: Calories and macros per 100g and per serving for everyday foods.
Sources
Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51(2):241-7. doi:10.1093/ajcn/51.2.241
National Academies. Dietary Reference Intakes: RDA for protein, 0.8 g per kg body weight a day.
Dietary Guidelines for Americans, 2025-2030: protein goal of 1.2-1.6 g per kg body weight a day.
Jäger R et al. J Int Soc Sports Nutr 2017;14:20.
Morton RW et al. Br J Sports Med 2018;52:376-84.
Formula and text last reviewed on 24 September 2026.
This calculator gives general estimates for healthy adults and is not medical advice. If you are pregnant, breastfeeding, or have a medical condition or an eating disorder, talk to a doctor or dietitian before changing how you eat.