Macro calculator
Calories decide which way your weight moves. Protein, fat and carbohydrate decide what it is made of. Enter your details and goal and the calculator splits your daily intake into grams: protein from body weight, fat from calories, carbs as the remainder.
| Nutrient | Grams per day | kcal | Share |
|---|---|---|---|
| Protein | — | — | — |
| Fat | — | — | — |
| Carbs | — | — | — |
| Fiber | 30 g | — | — |
Protein 1.8 g per kg, fat 30% of calories, carbs as the remainder. Where those numbers come from is set out below, with links to the research.
The order is deliberate
Protein is fixed first because it decides whether you keep muscle in a deficit and build it in a surplus. Fat comes second because it has a physiological floor. Carbohydrate takes whatever is left and acts as the regulator, since it is the easiest macro to move when calories change.
Why protein is set per kilogram, not as a percentage
A percentage of calories looks tidy but breaks at the edges: in a hard deficit, twenty percent of calories is too little protein to protect muscle, while in a large surplus the same percentage becomes excessive. Grams per kilogram of body weight stays stable as calories change, which is why sports nutrition literature sets it that way.
Macros and lifting
If you train with weights, the split matters more than it looks. A deficit without enough protein takes muscle along with the fat, and your working weights start to fall, which is the first visible sign the split is wrong. Judge it from your training log rather than the mirror: if weights and reps hold, body composition is moving the right way.
Method and sources
Reviewed byAnna Yusupova, fitness coach · Updated:
The protein range and fat share come from published research, with APX product settings named separately.
The choice of equation, the protein range and the fat share come from published research. The rest are APX product settings: a 275 kcal step per 0.25 kg per week, a safety floor of 1,500 kcal for men and 1,200 for women, and returning only half of your active calories rather than all of them, because wearables systematically overestimate expenditure. Any maintenance number is a population estimate. Two people with the same height and weight burn different amounts, so treat the number as a starting point and check it against two to three weeks of weight data.
- 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. The American Journal of Clinical Nutrition, 51(2), 241–247 Used for: the resting metabolic rate equation this calculator is built on
- 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. British Journal of Sports Medicine, 52(6), 376–384 Used for: the protein range for people who lift, which is where 1.8 g per kg comes from
- National Academies of Sciences (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids. Institute of Medicine, Macronutrients chapter Used for: the acceptable fat range that the 30% of calories default sits inside
- NIDDK, National Institutes of Health. Body Weight Planner: a dynamic model of body weight change. Laboratory of Biological Modeling Used for: why a target date cannot be found by dividing a deficit by 7,700 kcal
This calculator is an educational estimate, not medical advice. Talk to a doctor before major changes to your training or diet.
Frequently asked questions
How much protein do I actually need?
This calculator uses 1.8 g per kg of body weight. That sits at the top of the range from the Morton meta-analysis, which found gains in muscle and strength plateau around 1.6 g per kg with a confidence interval reaching about 2.2. If you are not doing resistance training, you do not need this much.
Why exactly 30 percent fat?
It is the middle of the acceptable range defined by the US National Academies, which is 20 to 35 percent of calories. Below 20 percent hormone production and fat-soluble vitamin absorption start to suffer. Above 35 percent, in a deficit, there is rarely enough room left for the carbohydrate that fuels training.
What about carbohydrates?
Carbs are the remainder here: protein is fixed first, then fat, and what is left goes to carbohydrate. That order suits people who train. Protein protects muscle, fat covers the hormonal minimum, and carbohydrate becomes the lever that is easiest to move when calories need adjusting.
Do I have to hit the grams exactly?
No. Hit your protein, stay roughly inside your calorie range, and a ten to fifteen percent swing between fat and carbs will not change your results. Chasing gram-level precision produces more abandoned diets than progress.
And fiber?
It sits in the table as a separate line with a target of 30 g a day and is not counted in calories. That is a sensible order of magnitude rather than a hard rule: fiber has a large effect on satiety, which in turn decides whether you can hold a deficit at all.
Protein only works with a training stimulus
APX builds your lifting plan and logs every set, so your split has something to back it up.
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