Free calculator

Macro calculator to lose fat or build muscle

Calculate how many grams of protein, carbs and fat to eat a day to lose fat, maintain or build muscle. They're the same rules the Mobbe app uses to set your daily target.

Your macros to lose weight

2,250kcal a day

Recommended pace: 0.6 kg a week, 0.75% of your weight.

Protein: 170 g30% of calories · 2.0 g per kg
Carbs: 201 g36% of calories
Fat: 85 g34% of calories · 1.0 g per kg

Fiber: at least 32 g a day. Maintenance: 2,950 kcal.

Your pace

Sustainable2,450 kcal · 0.4 kg a weekRecommended2,250 kcal · 0.6 kg a weekSuggestedAggressive2,000 kcal · 0.85 kg a week

You only see the paces that are safe for your profile.

It's an estimate, not a measurement. In the app, reviews compare it with your real weight and suggest adjustments. It doesn't replace a professional: during pregnancy or breastfeeding, or with an eating disorder, diabetes, kidney disease or weight-loss treatment, the app doesn't calculate targets and suggests seeing a professional.

Take it to your plan. Mobbe builds your routine for free and, with PRO, your meals with these grams.

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The method

How we calculate

The same calculation the Mobbe app does, step by step and with the worked example.

Step 1
Your calories
First, your daily target: your maintenance with the pace you choose to lose or gain, as in the calorie calculator. In the example (a 30-year-old man, 180 cm, 85 kg, 4 training days a week, losing weight) it's 2,250 kcal.
Mifflin-St Jeor and NASEM, 2023. Paces from Helms, 2014 and Garthe, 2011.
Step 2
Protein first
Per kg of weight: 2.0 g to lose, 1.6 to maintain and 1.8 to build muscle (2.0 if you're vegan). From age 65, 0.2 more. With a BMI of 27.5 or more, a reference weight is used, the one you'd have at a BMI of 27.5, except when building muscle. In the example: 2.0 × 85 = 170 g.
protein = g per kg × weight (or reference weight)
Helms, 2014; Hector and Phillips, 2018; Morton, 2018; Iraki, 2019. Older adults: PROT-AGE, 2013. Reference weight: Weijs, 2025.
Step 3
Fat
1 g per kg of weight (or reference weight), always between 20 and 35% of calories and never below 0.5 g per kg. In the example: 85 g, 34% of calories.
ISSN, 2018 (Kerksick and colleagues) and IOM, 2005.
Step 4
Carbs and fiber
Carbs fill in the rest of the calories, with a minimum of 130 g. If they fall short, fat goes down to its floor first and, only when losing weight, protein down to 1.6 g per kg. In the example: (2,250 − 4 × 170 − 9 × 85) ÷ 4 = 201 g. Fiber: 14 g per 1,000 kcal, at least 25 g (32 g in the example).
carbs = (kcal − 4 × protein − 9 × fat) ÷ 4
IOM, 2005.

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):241-247. doi:10.1093/ajcn/51.2.241
National Academies of Sciences, Engineering, and Medicine. Dietary Reference Intakes for Energy. Washington, DC: The National Academies Press; 2023. doi:10.17226/26818
Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. J Int Soc Sports Nutr. 2014;11:20. doi:10.1186/1550-2783-11-20
Helms ER, Zinn C, Rowlands DS, Brown SR. A systematic review of dietary protein during caloric restriction in resistance trained lean athletes: a case for higher intakes. Int J Sport Nutr Exerc Metab. 2014;24(2):127-138. doi:10.1123/ijsnem.2013-0054
Hector AJ, Phillips SM. Protein recommendations for weight loss in elite athletes: a focus on body composition and performance. Int J Sport Nutr Exerc Metab. 2018;28(2):170-177. doi:10.1123/ijsnem.2017-0273
Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376-384. doi:10.1136/bjsports-2017-097608
Iraki J, Fitschen P, Espinar S, Helms E. Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports (Basel). 2019;7(7):154. doi:10.3390/sports7070154
Bauer J, Biolo G, Cederholm T, et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc. 2013;14(8):542-559. doi:10.1016/j.jamda.2013.05.021
Weijs PJM. Protein requirement in obesity. Curr Opin Clin Nutr Metab Care. 2025;28(1):27-32.
Kerksick CM, Wilborn CD, Roberts MD, et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr. 2018;15(1):38. doi:10.1186/s12970-018-0242-y
Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: National Academies Press; 2005. doi:10.17226/10490
Garthe I, Raastad T, Refsnes PE, Koivisto A, Sundgot-Borgen J. Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. Int J Sport Nutr Exerc Metab. 2011;21(2):97-104. doi:10.1123/ijsnem.21.2.97

Questions

Frequently asked questions

How are macros calculated?

You start from your daily calories. First protein is set per kg of weight based on your goal, then fat (1 g per kg, between 20 and 35% of calories), and carbs fill in what's left, with a minimum of 130 g. Each gram of protein or carbs provides 4 kcal and each gram of fat, 9.

What macros do I need to build muscle?

Protein at 1.8 g per kg (2.0 if you're vegan), fat at 1 g per kg and the rest in carbs, with a small calorie surplus. A 30-year-old man, 180 cm and 85 kg, who trains 4 days a week needs about 3,150 kcal: 153 g of protein, 443 g of carbs and 85 g of fat.

What macros should I use to lose fat?

More protein (2.0 g per kg) to protect your muscle, fat at 1 g per kg and carbs with what's left of your deficit. At 85 kg and 4 training days: 2,250 kcal, 170 g of protein, 201 g of carbs and 85 g of fat. A 30-year-old woman, 165 cm and 62 kg, who trains 3 days: 1,800 kcal, 124 g of protein, 187 g of carbs and 62 g of fat.

How much fiber should I eat?

About 14 g per 1,000 kcal, and at least 25 g a day (IOM 2005). At 2,250 kcal that's 32 g.

Does it work if I'm vegetarian or vegan?

Yes. Choose your diet in the calculator: if you're vegan, protein goes up to 2.0 g per kg when building muscle. In every other case the grams are the same; what changes is which foods they come from.

Why does the calculator use a reference weight?

Because with a lot of body fat, calculating protein and fat on total weight gives higher numbers than you need. With a BMI of 27.5 or more it uses the weight you'd have at a BMI of 27.5 (Weijs 2025). When building muscle, protein is calculated on your real weight.

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Download Mobbe and answer a few questions: it builds your routine for free and, with PRO, your meal plan with grams and macros comes from these same calculations. Swap a food and it recalculates the grams.