A macro calculator turns your daily calorie target into grams of protein, carbohydrate and fat. Protein and carbs provide 4 calories per gram and fat provides 9. A common starting split for fat loss is 35% protein, 35% carbs and 30% fat, which for a 1,903-calorie target is about 167 g protein, 167 g carbs and 63 g fat.
Key takeaways
- Calories decide whether you lose or gain weight; macros decide what that weight is made of and how full and energized you feel.
- Protein first is a practical method: set protein from body weight (about 0.9 g per pound), fat at roughly 25% of calories, and let carbs fill the rest.
- The same calorie target gives very different grams on a balanced, lower-carb or keto split, so pick the style you can stick to.
- Split your protein across 3–5 meals and adjust after 2–4 weeks of real weight-trend data.
How does this macro calculator work?
Enter your sex, age, weight, height, activity level and goal (lose, maintain or gain). The calculator estimates your calories with the Mifflin–St Jeor equation (Mifflin et al., 1990), applies a moderate adjustment for your goal, and shows grams of protein, carbs and fat with each as a share of calories. It also divides the grams across 3, 4 or 5 meals.
Choose a diet style (Balanced, Lower carb, High protein, Endurance or Keto) or switch to Protein-first, which sets protein at 2.0 g per kg (0.9 g per lb) and fat at 25% of calories. A small table then shows every diet style at your calorie target, so you can compare them directly.
What are macros and how many calories do they have?
Macronutrients are the three nutrients that provide calories: protein (4 kcal per gram), carbohydrate (4 kcal per gram) and fat (9 kcal per gram). Alcohol adds 7 kcal per gram but isn’t counted as a macro here.
protein grams = calories × protein share ÷ 4 carb grams = calories × carb share ÷ 4 fat grams = calories × fat share ÷ 9
Worked example: macros for weight loss
Take a 35-year-old woman who is 5′5″ (165 cm), weighs 165 lb (74.8 kg) and is moderately active. Her estimated TDEE is 2,239 kcal. A 15% reduction gives a target of 1,903 kcal, and the default fat-loss split is 35% protein, 35% carbs and 30% fat.
| Macro | Share of calories | Calories | Grams per day |
|---|---|---|---|
| Protein | 35% | 666 | 167 g |
| Carbohydrate | 35% | 666 | 167 g |
| Fat | 30% | 571 | 63 g |
Spread across four meals, that is about 42 g protein, 42 g carbs and 16 g fat per meal. The same approach works for any body: change the inputs and the grams change with them.
Macros by diet style
Here is the same 1,903-calorie target on each diet style the calculator offers.
| Diet style | Protein / Carbs / Fat share | Protein | Carbs | Fat |
|---|---|---|---|---|
| Balanced | 30 / 40 / 30 | 143 g | 190 g | 63 g |
| Lower carb | 35 / 25 / 40 | 167 g | 119 g | 85 g |
| High protein | 40 / 35 / 25 | 190 g | 167 g | 53 g |
| Endurance | 25 / 55 / 20 | 119 g | 262 g | 42 g |
| Keto | 25 / 5 / 70 | 119 g | 24 g | 148 g |
| Protein-first | 2.0 g/kg, 25% fat, carbs fill the rest | 150 g | 207 g | 53 g |
Protein-first is useful when you weigh more or less than average: your protein follows your body weight instead of a percentage of calories.
Macro calculator for weight loss
For fat loss, keep protein high and let carbs and fat flex. A deficit of 10–20% below maintenance is a common range; see the calorie deficit calculator to choose a pace. Protein at roughly 1.6–2.2 g per kg (0.7–1.0 g per lb) is the range most often used for people who lift while losing weight (Jäger et al., 2017; Morton et al., 2018), and the protein calculator gives your exact range.
Do not set calories below about 1,200 (women) or 1,500 (men) without medical supervision, and never below your BMR for long. See the BMR calculator.
Macro calculator for women
The math is the same for women and men. What differs is the starting calorie estimate, because the Mifflin–St Jeor equation subtracts 161 for women and adds 5 for men, which reflects average differences in lean mass. A 30-year-old man at 5′10″ and 190 lb who is moderately active has a fat-loss target of 2,408 kcal, with 211 g protein, 211 g carbs and 80 g fat on the same 35/35/30 split.
Women who are pregnant or breastfeeding have different needs; use the TDEE calculator for women for calorie math and speak to a clinician for guidance. A macro split is not medical advice.
Macros to build muscle
For a gain goal the calculator adds a modest surplus and shifts calories toward carbohydrate: the default split is 25% protein, 50% carbs and 25% fat. The woman in the example above would eat about 2,463 kcal with 154 g protein, 308 g carbs and 68 g fat. Use the calorie surplus calculator to size the surplus to your training experience.
When should I adjust my macros?
Treat the first result as a starting estimate. Track your weight and intake for 2–4 weeks; if your trend doesn’t match the plan, change calories by about 100–200 per day. Protein generally stays put. Your maintenance calories are the anchor for every adjustment.
The recommended minimum protein intake for adults is 0.8 g per kg (Institute of Medicine, 2005), which is a floor to avoid deficiency, not a target for body composition.
Frequently asked questions
What is the best macro split for weight loss?
There is no single best split. A higher-protein split such as 35% protein, 35% carbs and 30% fat is a sensible default because protein helps you stay full and hold on to muscle in a deficit. The best split is the one that fits your food preferences so you can follow it for months.
How do I calculate macros for weight loss?
First find your maintenance calories, then subtract 10–20% for a deficit. Next set protein at roughly 0.7–1 g per pound of body weight, fat at about 25–30% of calories, and fill the rest with carbs. The calculator above does these steps and shows the grams per meal.
How many grams of protein, carbs and fat should a woman eat?
It depends on size, activity and goal, not on sex alone. For a 35-year-old woman at 165 lb eating 1,903 calories to lose fat, a 35/35/30 split gives about 167 g protein, 167 g carbs and 63 g fat. Smaller or less active women will have lower totals.
Do I need to hit my macros exactly?
No. Daily intake varies, and food labels are approximate. Aim to land within 5–10 g of your protein target most days and within roughly 100 calories of your calorie target. Consistency over weeks matters far more than perfection on any single day.
Should I count macros or just calories?
Calories alone drive weight change, so many people do well tracking only calories and protein. Tracking carbs and fat as well helps if you train hard, follow a specific diet style, or want tighter control over how your food is split.
References
- Institute of Medicine (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. The National Academies Press.
- Jäger R, Kerksick CM, Campbell BI, et al. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition 14:20.
- Morton RW, Murphy KT, McKellar SR, et al. (2018). 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. British Journal of Sports Medicine 52(6):376–384.
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition 51(2):241–247.