DocomintMacro Calculator
Split daily calories into protein, carb, and fat gram targets by percentage.
What is a Macro Calculator?
Converts a calorie budget and a macro split (like the common 30/40/30 protein/carb/fat ratio) into actual gram targets — the number that matters when reading a nutrition label — using each macronutrient's calories-per-gram (protein and carbs at 4, fat at 9), which is why the same percentage split doesn't translate to the same gram amounts across macros.
How to use the Macro Calculator
- Enter your daily calorie target and a protein/carb/fat percentage split
- Press Calculate
- Gram targets for each macronutrient appear instantly, computed on your device
Formula
Grams = (Calories × Macro%) ÷ Calories-per-gram (Protein: 4, Carbs: 4, Fat: 9)
Each macronutrient's percentage share of total calories is converted to grams using its specific calories-per-gram figure — fat's higher 9 cal/g means the same percentage share yields fewer grams than protein or carbs.
Example
2,200 daily calories split 30/40/30 works out to 165g protein, 220g carbs, and 73g fat — note fat's gram target is disproportionately lower than protein's despite an equal 30% calorie share, since fat packs more than double the calories per gram.
Common mistakes
- Assuming an equal percentage split produces equal gram amounts across the three macros — fat's 9 cal/g means the same % share always yields noticeably fewer grams.
- Entering percentages that don't sum to 100 — the calculator flags this rather than silently normalizing an inconsistent split.
- Forgetting to update the calorie total when goals change, which throws off all three gram targets proportionally.
Frequently asked questions
Why don't macro percentages match gram percentages?
Because protein, carbs, and fat have different calories per gram (protein and carbs: 4 each; fat: 9) — a 30% calorie share for fat translates to fewer grams than the same 30% share for protein or carbs, since each fat gram carries more than double the calories.
What macro split should I use?
It depends on your goals — a common general-fitness starting point is roughly 30% protein / 40% carbs / 30% fat, but athletes, low-carb diets, and other specific goals often use very different ratios. Adjust the three percentages here to match whatever plan you're following.
Where do I get my daily calorie target for this?
See Calorie Calculator, which estimates maintenance calories (or a deficit/surplus target) from your weight, height, age, and activity level — plug that figure into this tool's "Daily calories" field.
What macro split is best for muscle gain?
A commonly used starting point emphasizes higher protein (roughly 30-35%) to support muscle repair, with the remainder split between carbs (for training energy) and fat — exact ratios vary by individual goals and training volume, so treat any specific split as a starting point to adjust.
Is my numbers uploaded anywhere?
No — Macro Calculator runs entirely in your browser using JavaScript/WebAssembly. Your numbers is never sent to a server.