Macro calculator: protein, fat and carbs in grams
Macros are your daily calories, protein, fat and carbs. The calculator works out calories with the Mifflin-St Jeor equation (1990), multiplies them by an activity level and splits them for your goal: protein in grams per kilo of body weight (how much depends on your goal and whether you train), fat at a quarter of calories, carbs the rest. For example, a 30-year-old woman, 65 kg, 165 cm, lightly active, needs 1,507 kcal to lose weight: 117 g protein, 40 g fat and 170 g carbs.
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Where the number comes from
The formula, a worked example and where it stops working
What macros are
Macros, short for macronutrients, are protein, fat and carbohydrates — the three things in food that carry calories. Your macro targets are your daily calories split into grams of each, matched to your goal.
The calculator works out calories with the Mifflin-St Jeor equation (Mifflin MD, St Jeor ST et al., American Journal of Clinical Nutrition, 1990), adjusted for activity and goal. Where those calories come from is covered in detail in the TDEE calculator, and if you want to lose weight, the pace is set by the calorie deficit calculator. This page is about the next step: splitting the calories into protein, fat and carbs.
Turning calories into grams is simple: a gram of protein or carbs has about 4 kcal, a gram of fat about 9 (the general Atwater factors, FAO, 2003). So 30% of calories from fat is 2.25 times fewer grams than 30% from carbs.
Which macro split fits your goal
The calculator starts with protein and sets it in grams per kilo of body weight, not as a share of calories. How many grams depends on your goal and on whether you train. If you train, which means light activity (1-3 workouts a week) or more: 1.8 g/kg for weight loss, 1.4 for maintenance, 1.6 for gain and 2.0 for recomposition. That sits inside the 1.4-2.0 g/kg range the International Society of Sports Nutrition (ISSN) 2017 position stand calls enough for most people who train. The same paper says that in a calorie deficit you may need more, which is why protein is higher when cutting. If you are sedentary, the calculator assumes you don't train: 0.83 g/kg at maintenance, the EFSA reference intake for adults, 1.2 g/kg for weight loss and 1.4 for gain and recomposition.
Fat is set at 25% of calories and carbs get the rest. All three shares stay inside the US Institute of Medicine acceptable ranges: protein no more than 35% of calories, fat 20-35%, carbs 45-65% and at least 130 g. When calories are low, fat drops closer to 20% so there is room for carbs. If you prefer a little more fat and fewer carbs at the same calories, it barely changes your weight: calories and protein do the heavy lifting.
- Weight loss — protein 1.8 g/kg if you train, 1.2 g/kg if you don't (ISSN 2017 and Leidy 2015). Fewer calories, but more protein than at maintenance
- Maintenance — protein 1.4 g/kg if you train, 0.83 g/kg if you don't (ISSN 2017 and EFSA 2012), fat 25%, carbs the rest
- Muscle gain — protein 1.6 g/kg, inside the ISSN 2017 range. Most of the extra calories go into carbs
- Recomposition — maintenance calories and protein at 2.0 g/kg, the top of the ISSN 2017 range
How to calculate macros: a step-by-step example
A woman of 30, 65 kg, 165 cm, light activity (1-3 workouts a week), aiming to lose weight at a moderate pace. Her daily burn is 1,884 kcal. The moderate pace means 500 off, but that is more than 20% of her burn, so the calculator takes 377 kcal off: 1,507 kcal a day. From there the number is split exactly as the calculator above does it.
- protein: light activity already counts as training, so 1.8 g/kg (ISSN 2017). 65 kg × 1.8 g = 117 g, which is 468 kcal or 31% of calories
- fat: at 25% of calories carbs would get less than 45%, so the calculator lowers fat just enough to leave room for them: 40 g, 24% of calories
- carbs are the rest: (1,507 − 468 − 360) ÷ 4 = 170 g, 45% of calories, the bottom of the IOM range of 45-65%
- check with the 4 and 9 kcal factors: 117 × 4 + 40 × 9 + 170 × 4 = 1,508 kcal — one calorie off from rounding the grams
- if the same woman just holds her weight, the calculator gives 1,884 kcal and the split becomes 91 g protein, 52 g fat, 263 g carbs
- if she didn't train at all (sedentary), the calculator would put her burn at 1,644 kcal, and cutting she would get 1,315 kcal with 78 g of protein, 1.2 g/kg
Macros for different goals: woman
One woman, four goals, sedentary with no workouts. The calculator sets protein for someone who doesn't train: 54 g at maintenance, the EFSA 0.83 g/kg, and more when cutting, 78 g or 1.2 g/kg.
For gain and recomposition protein is 91 g, the bottom of the ISSN 2017 range at 1.4 g/kg. These goals don't really work without training, so pick them if you train.
| Goal | Calories | Protein, g | Fat, g | Carbs, g |
|---|---|---|---|---|
| Weight loss | 1,315 | 78 g | 37 g | 168 g |
| Maintenance | 1,644 | 54 g | 46 g | 254 g |
| Gain | 1,809 | 91 g | 50 g | 249 g |
| Recomposition | 1,644 | 91 g | 46 g | 217 g |
Woman, 30, 65 kg, 165 cm, sedentary (×1.2), so protein is set for someone who doesn't train: 1.2 g/kg for weight loss, 0.83 for maintenance, 1.4 for gain and recomposition.
Macros for different goals: man
The same split for a man of 30, 80 kg, 178 cm who trains 3-5 times a week, which is moderate activity. More calories, and protein follows the ISSN range for people who train.
Look at protein: it comes from body weight, not from calories. When cutting he gets 144 g, 1.8 g/kg; on recomposition 160 g, 2.0 g/kg. The calculator never goes above 2.0 g/kg, and protein never takes more than 35% of calories. If you only want to track protein, the protein calculator per kg of body weight gives the same grams.
| Goal | Calories | Protein, g | Fat, g | Carbs, g |
|---|---|---|---|---|
| Weight loss | 2,240 | 144 g | 62 g | 277 g |
| Maintenance | 2,740 | 112 g | 76 g | 402 g |
| Gain | 3,014 | 128 g | 84 g | 437 g |
| Recomposition | 2,740 | 160 g | 76 g | 354 g |
Man, 30, 80 kg, 178 cm, moderate activity (×1.55), so protein is set for someone who trains: 1.8 / 1.4 / 1.6 / 2.0 g/kg.
When the split does not fit
Some cases call for macros set by a doctor, not a calculator. The general limits of the calorie formula — pregnancy, teenagers, thyroid disease, lots of muscle — are listed in the calorie calculator. Here is what applies to macros specifically.
- Kidney or liver problems — the protein share is decided with a doctor only
- Diabetes and other conditions where carbs are counted on medical advice
- A past or current eating disorder — strict macro counting can do harm
What to do with the split next
Do not try to hit three numbers to the gram. The order is: hold your calories first, then get your protein in, and fat and carbs will sort themselves out.
The hardest part is home cooking where everything is mixed together. For soups, stews and patties there is the recipe calorie calculator, which gives macros per 100 g and per portion. More on hitting your macros day to day in the article on daily macro requirements.
How we calculate
The formulas and limits are the same as in the CalCash bot: the site and the bot run the same code. Here is what goes into the number.
- Resting burn (BMR) — the Mifflin-St Jeor equation: 10 × weight in kg + 6.25 × height in cm − 5 × age, plus 5 for men or minus 161 for women (Mifflin MD, St Jeor ST et al., American Journal of Clinical Nutrition, 1990).
- Daily burn (TDEE) — BMR × an activity factor from 1.2 to 1.9. The idea of "BMR × physical activity level" comes from FAO/WHO/UNU, Human energy requirements, chapter 5, 2004. The 1.2–1.9 numbers themselves are the factors calculators commonly use; we could not trace their original source, so we do not pin them on anyone.
- Weight loss — minus 250, 500 or 750 kcal a day depending on pace, but never more than 20% of your burn. The 500 kcal step is the low end of the 500–1,000 kcal a day deficit in the NHLBI guidelines, 1998; 250 is gentler still. The 20% cap is our cautious choice, not a number from a study: we could not find a verified source for an exact percentage.
- Minimum while losing weight — 1200 kcal for women and 1500 for men, the top ends of the 1000–1200 and 1200–1500 kcal ranges in NHLBI, Clinical Guidelines on Overweight and Obesity in Adults, 1998. From age 60 the calculator keeps 1400 and 1600; that is our cautious choice. If your burn is below the minimum, the target equals your burn: eating more than you burn makes no sense when losing weight.
- Gain — plus 10% of your burn, the low end of the 10–20% surplus in the review by Iraki J, Fitschen P, Espinar S, Helms E, Sports, 2019. Recomposition — maintenance calories: sources give no exact number for it, so maintenance is our cautious choice.
- Protein — in grams per kilogram of body weight, and it depends on activity. Without training (sedentary): 0.83 g/kg to maintain, the adult reference intake (EFSA, population reference intakes for protein, 2012); 1.2 g/kg to lose weight, the bottom of the 1.2–1.6 g/kg range from a review of protein in weight loss (Leidy HJ et al., American Journal of Clinical Nutrition, 2015); 1.4 g/kg for gain and recomposition. From light activity (1-3 workouts a week) up: 1.8 for weight loss, 1.4 for maintenance, 1.6 for gain, 2.0 for recomposition, inside the 1.4–2.0 g/kg range for people who train (International Society of Sports Nutrition Position Stand, 2017). Where the "trains" line sits and which numbers we pick inside the ranges is our choice.
- Shares stay inside the acceptable ranges (US Institute of Medicine, Dietary Reference Intakes summary tables, 2005): protein no more than 35% of calories, fat 20–35%, carbs 45–65% and at least 130 g. The calculator sets fat at 25%, which is also under the WHO advice to keep fat at 30% or less (WHO fact sheet «Healthy diet», checked 19 October 2026). When calories are low, fat drops to 20% first, then protein moves down to its minimum.
- Grams from calories use the general Atwater factors: 4 kcal per gram of protein and carbs, 9 per gram of fat (FAO, Food energy — methods of analysis and conversion factors, 2003).
Holding calories and all three macros in your head is hard work. That is the job of a bot that reads macros off a photo of your plate: it breaks every meal into protein, fat and carbs and checks it against your split for the day.
Frequently asked questions
How do I calculate my macros?
Start with your calorie target: Mifflin-St Jeor BMR × an activity factor, minus a deficit if you are cutting. Then protein: body weight × a factor. If you train, that is 1.8 g when cutting and 1.4 at maintenance; if you don't, 1.2 and 0.83. Fat is 25% of calories and carbs are the rest. To get grams, protein and carbs have 4 kcal per gram, fat has 9. The calculator on this page does every step at once.
Can I tweak the macro split manually?
The calculator sets protein for your goal and splits fat and carbs by share. If you want a different split, keep calories and protein and trade fat against carbs: fat between 20 and 35% of calories, carbs at least 130 g (US Institute of Medicine ranges). For grams: calories × share ÷ 9 for fat, ÷ 4 for carbs.
Is protein here the same as in the protein calculator?
Yes. Both use the same formula: grams per kilo of body weight by goal and activity: for example, cutting with training is 1.8 g/kg, so 117 g at 65 kg. Both also keep protein at no more than 35% of calories. The macro calculator used to take protein as a share of calories and gave more; now the numbers match.
How is this different from a calorie calculator?
A calorie calculator gives you one number for the day. The macro calculator takes that number and splits it into grams of protein, fat and carbs, so you can see what the calories should be made of.
Do I recalculate the split after losing weight?
Yes, every 3-4 kg. Weight sits in the formula, so calories and all three macros move with it. A target that worked at the start is too high at your new weight — which is usually where a plateau begins.
How many extra calories should I eat to bulk?
The muscle gain goal here gives your burn plus 10%, the low end of the 10-20% range in the review by Iraki and colleagues, 2019. The bot counts it the same way. For more on pace, use the calorie surplus calculator: pick +10% or +20% and see the expected weekly gain.
Reminders
Water and weight