Fitness · 5 min read
How to Calculate Protein and Macros
Grams from calories and g/kg protein — a planning split, not a diet
Macronutrients convert calorie shares into grams: protein and carbohydrate at 4 kcal/g, fat at 9 kcal/g. This tutorial sets protein from body weight (g/kg), then splits the remaining calories between carbs and fat. The split is a teaching estimate, not medical advice, not a diagnosis, and not a meal plan.
Written by the My Calculator Stack editorial team. About our methods
This is not medical advice, not a diagnosis, and not an individualized nutrition plan. Protein g/kg ranges and carb/fat splits are coarse planning tools. Needs change with training, illness, pregnancy, kidney disease, and other conditions. Talk to a qualified clinician or registered dietitian before changing how you eat.
1.What macros are
Protein, carbohydrate, and fat are the energy macronutrients. A common teaching sequence is: pick daily calories, set protein from body weight, then split whatever calories remain between carbs and fat. The numbers are arithmetic, not a prescription. They do not diagnose a deficiency or replace a dietitian. For the calorie total itself, start from TDEE or BMR rather than guessing an intake.
2.The formula
Protein grams = weight (kg) × g/kg. Common planning bands run from about 0.8 g/kg (a typical adult RDA-style floor) through 1.2–2.2 g/kg for more active people — those bands are not a diagnosis. Protein kcal = grams × 4. Remaining kcal = calories − protein kcal. If a fraction c of the remainder goes to carbohydrate, carb grams = c × remaining / 4 and fat grams = (1 − c) × remaining / 9. Percents of total calories are those gram-calories divided by the daily calorie figure.
\[ \begin{aligned}P &= w \times g_{\mathrm{kg}} \\C &= \frac{c\,(\mathrm{Cal}-4P)}{4},\quad F = \frac{(1-c)\,(\mathrm{Cal}-4P)}{9}\end{aligned} \]
3.Worked example
Take 2200 kcal/day, 70 kg, and 1.6 g protein per kg — a mid-range planning factor, not a clinical target. Protein = 70 × 1.6 = 112 g = 448 kcal. Remaining = 2200 − 448 = 1752 kcal. Put 60% of that remainder on carbohydrate and 40% on fat: carbs = 0.60 × 1752 / 4 = 262.8 g, fat = 0.40 × 1752 / 9 = 77.9 g. As shares of 2200 kcal that is about 20% protein, 48% carbohydrate, and 32% fat. Change the g/kg factor or the carb/fat split and the bars move; the arithmetic is not medical advice.
\[ P=70\times 1.6=112\,\mathrm{g},\ C=262.8\,\mathrm{g},\ F=77.9\,\mathrm{g} \]
4.Protein and split bars
Set calories, body weight, and protein grams per kilogram, then move the carb/fat remainder split. The stacked bar shows protein, carbohydrate, and fat as calorie shares. This is a teaching widget — no favorites, no full calculator chrome. There is no dedicated macros tool on the calorie page; use the TDEE and BMR tutorials for the energy total, then browse fitness calculators for related screening tools.
Inline playground
Fat takes the rest of remaining calories.
Macros (planning split)
P 112 g · C 262.8 g · F 77.9 g
70 × 1.6 = 112 g protein
Screening aid only — not medical advice, not a diagnosis, not a meal plan.
5.Where to go next
Daily calories usually start from TDEE (BMR times activity). Open How to Calculate Daily Calories (TDEE) or How to Calculate BMR, then browse fitness calculators if you want BMI, body-fat, or calorie-target tools on one hub. Treat every split as a sketch, not a diagnosis.
Try it yourself
Open the related calculator and put these formulas to work.