Macro Calculator — protein, carbs & fat split
Split your daily calories into grams of protein, carbs and fat from a preset or custom ratio — in your browser.
🔒 Runs entirely in your browser. Your input and output are never sent to a server or stored — fully private.
Enter your daily calories and choose a macro split to see your targets in grams.
Ratios are carbs / protein / fat as a % of calories.
Estimates only — not medical or nutritional advice.
About this tool
Have a daily calorie goal and want to know how it breaks down? Enter your target and pick a macronutrient ratio, and this calculator splits it into grams of protein, carbohydrate and fat. It works from the standard energy values — 4 calories per gram of protein and carbs, 9 per gram of fat — and shows each macro in grams and as a share of the day. It suits anyone tracking a diet or building a meal plan. The maths runs in your browser, so nothing you enter is uploaded.
Frequently asked questions
How are the grams worked out from calories?
Each macronutrient carries a fixed amount of energy: protein and carbohydrate give about 4 calories per gram, and fat gives about 9. The tool multiplies your calorie target by each macro's percentage, then divides by that energy value to get grams. For example, 30 percent of a 2,000-calorie day is 600 calories of protein, and 600 divided by 4 is 150 grams.
What macro ratio should I choose?
There is no single right answer; it depends on your goals and preferences. A balanced everyday split is around 30 percent protein, 40 percent carbohydrate and 30 percent fat, while low-carb plans push carbs down and fat up. Higher protein helps when you are building muscle or dieting. Start with a common preset, see how you feel and perform, and adjust the ratio from there.
Is this nutritional advice?
No. These numbers are a general starting point, not nutritional or medical advice. They say nothing about food quality, micronutrients, allergies or any health condition, and individual needs vary widely. For a plan tailored to you — especially if you are pregnant, diabetic or managing an illness — talk to a registered dietitian or doctor. Everything is calculated locally in your browser, and nothing you enter is uploaded or stored.