Macro Calculator
Split a daily calorie target into grams of protein, carbohydrate and fat with a preset ratio or your own percentages.
Turns a calorie number into grams of protein, carbs and fat.
How the macro calculator works
Macronutrients carry set energy: protein and carbohydrate 4 kcal per gram, fat 9 kcal per gram. Choose a split (balanced 30/40/30, higher-protein, lower-carb or higher-carb) or type your own percentages in Detailed mode, and the calculator converts each share of your calories into grams.
The presets are common starting points, not prescriptions. Most guidelines put protein between 10% and 35% of energy and fat between 20% and 35%; athletes and people losing weight often go higher on protein. Meals-per-day splits the grams evenly to make portions easier to picture.
Formula: grams = calories × share ÷ (4 for protein and carbs, 9 for fat)
Worked examples
| Inputs | Protein per day | Note |
|---|---|---|
| 2,200 kcal, balanced | 165 g | 165 g protein, 220 g carbs, 73 g fat |
| 1,800 kcal, higher protein | 180 g | a common cut: 180 g protein |
| 3,000 kcal, endurance split | 188 g | 412 g carbohydrate |
| 2,000 kcal, custom 35 / 35 / 30 | 175 g | custom shares in Detailed mode |
FAQFrequently asked questions
How many calories does each macronutrient have?
Protein 4 kcal per gram, carbohydrate 4 kcal per gram, fat 9 kcal per gram. Alcohol, if you count it, is 7.
How much protein do I need?
General guidance is about 0.8 g per kilogram of body weight a day for adults; people training hard or losing weight commonly aim for 1.6–2.2 g/kg. The protein-intake calculator works it out from your weight.
What if my custom percentages do not add to 100?
The calculator scales them so they do and tells you in a note. Percentages of a whole have to sum to 100 for the grams to match your calories.
Do the presets suit everyone?
They are common starting points. Medical conditions — diabetes, kidney disease, pregnancy — change what is appropriate, so check with a dietitian.
Where these figures come from
- Mifflin MD et al., "A new predictive equation for resting energy expenditure in healthy individuals", Am J Clin Nutr 1990 — the BMR equation used here
- World Health Organization — Waist circumference and waist–hip ratio (2008 expert consultation) — waist-to-hip cut-offs
- Tanaka H, Monahan KD, Seals DR, "Age-predicted maximal heart rate revisited", J Am Coll Cardiol 2001 — 208 − 0.7 × age
- Nathan DM et al., "Translating the A1C assay into estimated average glucose values" (ADAG), Diabetes Care 2008 — eAG = 28.7 × A1c − 46.7
- Mosteller RD, "Simplified calculation of body-surface area", N Engl J Med 1987 — BSA = √(height × weight / 3600)
- NHS — national health guidance
Last checked: September 2026. The equations are fixed by their published papers and do not change with tax years or regulations; the thresholds quoted in verdicts name the body that set them.