Macro Calculator
Calculate daily protein, carbs and fat in grams for your goal: lose weight, maintain or build muscle. Based on your calorie needs and expert protein targets.
🥗 Macro Calculator
Daily Targets (2,507 kcal)
💡 How the Macro Calculator Works
This calculator splits your daily calories into the three macronutrients: protein, carbohydrate and fat, in grams. It estimates your calorie needs from your body and activity, adjusts them for your goal, sets protein from your body weight and fat as a share of calories, and gives the rest to carbs. For a 30-year-old man of 70 kg and 170 cm with moderate activity who wants to maintain weight: 2,507 kcal, 140 g protein, 330 g carbs and 70 g fat a day.
How your macros are calculated
2. Protein: 2 g per kg of body weight (4 kcal per gram)
3. Fat: 25% of calories (9 kcal per gram)
4. Carbohydrate: the remaining calories (4 kcal per gram)
Worked example
- Calories: BMR 1,617.5 kcal × 1.55 = 2,507 kcal (maintain).
- Protein: 70 kg × 2 = 140 g = 560 kcal.
- Fat: 2,507 × 25% = 627 kcal ÷ 9 = 70 g.
- Carbs: (2,507 − 560 − 627) ÷ 4 = 330 g.
Macro targets for example people
| Person and goal | Calories | Protein | Carbs | Fat |
|---|---|---|---|---|
| Man, 30, 70 kg, 170 cm, moderate, maintain | 2,507 | 140 g (22%) | 330 g (53%) | 70 g (25%) |
| Woman, 35, 60 kg, 165 cm, moderate, lose | 1,508 | 120 g (32%) | 163 g (43%) | 42 g (25%) |
| Man, 25, 80 kg, 183 cm, active, gain | 3,646 | 160 g (18%) | 524 g (57%) | 101 g (25%) |
| Man, 40, 110 kg, 180 cm, sedentary, lose | 1,936 | 220 g (45%) | 143 g (30%) | 54 g (25%) |
Percentages show each macro's share of calories.
How the targets compare with expert guidance
The U.S. National Academies' Acceptable Macronutrient Distribution Ranges (set by the Institute of Medicine in 2005) are a widely used reference for adults:
| Macronutrient | Acceptable range (% of calories) | Calculator setting |
|---|---|---|
| Protein | 10–35% | 2 g per kg of body weight |
| Fat | 20–35% | 25% |
| Carbohydrate | 45–65% | Whatever remains |
For protein, the International Society of Sports Nutrition's 2017 position stand concludes that 1.4–2.0 g per kg a day is sufficient for most exercising people to build and maintain muscle, and that resistance-trained people cutting calories may benefit from more. The calculator's 2 g/kg sits at the top of that range, well above the general adult RDA of 0.8 g/kg, which is aimed at preventing deficiency rather than supporting training.
When to adjust the results
- If you carry a lot of body fat: protein set from total body weight can be very high. In the last example, a 110 kg man gets 220 g of protein, 45% of his 1,936 kcal, above the 35% upper guide, leaving carbs at 30%. Many dietitians base protein on goal weight or lean body mass instead; the lean body mass calculator helps.
- If you're losing weight on a small calorie budget: carbs can fall below 45% because protein stays fixed. That can be reasonable for a period, but make sure you still eat plenty of vegetables, fruit and whole grains for fibre.
- If you don't exercise: you may not need 2 g/kg. A lower protein target within the 10–35% range is fine for many sedentary adults.
- If you have kidney disease or another medical condition, or are pregnant, ask your doctor before following a high-protein target.
What each macronutrient does
- Protein (4 kcal/g) builds and repairs muscle and other tissue and is the most filling macronutrient. Good sources: meat, fish, eggs, dairy, legumes, tofu.
- Carbohydrate (4 kcal/g) is the body's main fuel, especially for hard exercise and the brain. Prioritise whole grains, fruit, vegetables and legumes.
- Fat (9 kcal/g) supports hormones, cell membranes and absorption of vitamins A, D, E and K. Favour unsaturated fats from olive oil, nuts, seeds and oily fish.
Spreading protein across meals is also useful. The ISSN suggests about 0.25 g per kg per meal, or 20–40 g, every few hours.
Turning grams into meals
Divide your daily grams by the number of meals. The example man's 140 g of protein over four meals is about 35 g each: roughly a chicken breast, a large pot of Greek yoghurt, or a plate of lentils and eggs. Food labels list grams of each macronutrient per serving, which makes tracking straightforward.
Safety on low-calorie goals
The weight-loss setting subtracts 500 kcal from your estimated needs. For smaller or less active people this can fall below the levels Harvard Health advises not going under without supervision (1,200 kcal a day for women, 1,500 for men), and the calculator shows a warning when it does. Your calorie estimate is a starting point; see the calorie calculator and TDEE calculator for more detail.
This calculator is for healthy adults. It isn't suitable for children, pregnant or breastfeeding women, or people with medical conditions. If you have a history of disordered eating, or plan a major change in diet, speak to a doctor or registered dietitian first.
Sources
- Jäger R, et al. (2017). International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition
- Acceptable Macronutrient Distribution Ranges, Food and Nutrition Board, Institute of Medicine (2005), summarised by the University of Minnesota
- Harvard Health Publishing: Calorie counting made easy
- Frankenfield D, et al. (2005), Journal of the American Dietetic Association: comparison of resting metabolic rate equations