How the macro calculator works
In evidence-based mode protein is set first, in grams per kilogram of body weight, because that's how research on resistance-trained people expresses requirements. Fat is then set as a share of calories (with a minimum of 0.5 g/kg), and carbohydrate fills the remaining energy. Carbs are the most flexible macro and the main fuel for hard training.
In diet-style mode the split comes from the typical macro distribution of a named approach (Mediterranean, ketogenic, zone, plant-based and so on). These splits are descriptive averages, so read the linked diet page to see what the approach actually involves.
Default protein by goal
Protein defaults to 2.2–2.4 g/kg when cutting (higher intakes appear to help retain lean mass in a deficit), 2.0 g/kg for a mild cut, and 1.7–1.8 g/kg for maintenance and bulking. These sit inside the 1.4–2.0 g/kg range of the ISSN position stand, extended upward for dieting lifters based on reviews of contest preparation.
Frequently asked questions
What are macros?
Macronutrients are the three nutrients that provide calories: protein (4 kcal/g), carbohydrate (4 kcal/g) and fat (9 kcal/g). Alcohol (7 kcal/g) is sometimes counted as a fourth. "Counting macros" means tracking grams of each rather than calories alone.
Is it better to set protein in g/kg or as a percentage?
If you train, grams per kilogram of body weight usually makes more sense, because protein needs scale with body size and lean mass, not with total calories. Percentages can leave you short on protein during a low-calorie cut and give you more than you need on a high-calorie bulk.
How much fat do I need?
The U.S. Acceptable Macronutrient Distribution Range for adults is 20–35% of calories from fat. Very low fat intakes over long periods aren't recommended, so this calculator never lets fat drop below 0.5 g per kg of body weight.
Do macros matter more than food quality?
Both matter. Macros set your energy balance and protein intake, which drive body composition. Food choices decide your fiber, vitamins and minerals, and how full you feel. Most evidence-based approaches recommend hitting your macro targets mainly with minimally processed foods.
How accurate do I need to be?
Landing within roughly ±10 g of protein and ±5–10% of calories on most days is enough for most people. Consistency over weeks matters more than precision on any single day.
Sources & further reading
- Jäger R, Kerksick CM, Campbell BI, et al. (2017). International Society of Sports Nutrition Position Stand: protein and exercise . J Int Soc Sports Nutr 14:20 · doi:10.1186/s12970-017-0177-8
- 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 . Br J Sports Med 52(6):376–384 · doi:10.1136/bjsports-2017-097608
- Institute of Medicine (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids . National Academies Press · doi:10.17226/10490
- Thomas DT, Erdman KA, Burke LM (2016). American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance . Med Sci Sports Exerc 48(3):543–568 · doi:10.1249/MSS.0000000000000852