How are my macros calculated?

We estimate BMR from your body, multiply by an activity factor for TDEE, apply a goal-based calorie shift, then balance protein, fat and carbs to hit that target.

How much protein do I need?

In a deficit, aim for 2.0–2.5 g per kg of lean mass. For muscle building, ~1.8 g per kg of body weight is usually enough.

What macros actually drive body recomposition?

A small calorie deficit (5 to 15 percent below TDEE), 1.6 to 2.2 g of protein per kg of bodyweight, fat at or above 0.7 g per kg, and carbs filling the remaining budget. The protein floor matters more than the carb-versus-fat split.

How accurate is a macro calculator?

The calorie target carries a typical ±10 percent error from BMR estimation. Eat at the calculator output for 7 to 10 days, watch the weight trend, then adjust calories by 100 to 200 kcal a week while holding the protein floor constant.

Macro Calculator: Calories, Protein, Fat and Carbs

What your macros actually mean

A macro target is three numbers (protein, fat, carbs) that add up to a calorie target. The calorie target sets the rough direction of bodyweight: a small deficit drives fat loss, maintenance defends what you have, a small surplus supports muscle gain. The macro split decides how much of that direction is composition: muscle preserved, muscle built, lean mass spared while fat comes off.

For body recomposition specifically, the recipe is narrow. A 5 to 15 percent calorie deficit, 1.6 to 2.2 g of protein per kg of bodyweight, fat at or above the 0.7 g/kg hormonal floor, and carbs filling the rest. The training has to do real work. Recomposition is the most precision-sensitive setting on the menu, but the macros side of it is genuinely simple once the protein floor is locked.

What changes is not the recipe but the calibration. Calculator BMR errors run about ±10 percent, NEAT swings hundreds of calories between people who look identical, and the body adapts down as the cut deepens. The numbers above are the starting line. The real workflow is checking the trend, holding the protein, and nudging the calorie target by 100 to 200 kcal until the scale matches the goal.

How to calculate your macros

We start from your BMR (Mifflin-St Jeor, or Katch-McArdle if you know your body fat) and multiply by an activity factor to get your maintenance calories (TDEE).

Then we apply a calorie shift based on goal, experience and body composition: a deeper deficit is safer with higher body fat, while a lean advanced lifter barely needs a surplus to keep gaining.

Most macro calculators give you a number. The answer that matters is the protein floor.

Body recomposition is fat loss and muscle gain at the same time, in the same calorie window. The split between carbs and fat is preference. The protein floor is the part the body actually scores you on. Miss it and the deficit takes muscle with the fat.

1.6–2.2g / kg bodyweight

The protein floor for recomposition. Below 1.6 the deficit pulls from lean tissue. Past 2.2 the curve flattens. Extra grams stop adding retention.

0.7g / kg bodyweight

Hormonal-health floor for dietary fat. Drop under it during a long cut and testosterone, sleep and recovery start to slide.

50g / day, minimum

Practical carbohydrate floor for training intensity and adherence. Cuts that go lower trade performance for marginal speed.

±10%of the calorie target

Typical error band on a calculator-based calorie target. The macro split sits inside that band, so weekly trend-based adjustment matters more than chasing a perfect % split on day one.

Protein scales to lean mass, not bodyweight. A 100 kg lifter at 12% body fat carries the same lean mass as a 100 kg lifter at 30%, but only the first one needs the same protein. That is why this tool prefers a g/kg-LBM target when body fat is known. It is also why the BMI calculator alone cannot answer this question.

Deeper deficits push the floor higher. In maintenance, 1.6 g/kg is enough to retain muscle. In a contest cut, the literature pushes that toward 2.4 g/kg because the body becomes more willing to break down lean tissue for fuel. The protein target rises with the deficit, not with the calorie target itself.

Below the floor, the macro split is preference. Once protein and the fat floor are met, carbohydrate vs fat distribution barely moves body composition over weeks. Pick the split you can actually adhere to. Recomposition is won by hitting protein every day for months, not by tuning the carb percentage on day one.