Use the free Macro Nutrient Calculator below: your data never leaves your browser — all work happens on your device, and nothing is uploaded to any server.
What This Calculator Does
A macro nutrient calculator splits your daily calories into protein, carbohydrates, and fat. These three are called macronutrients, or macros for short. They are the nutrients that supply energy. Protein builds and repairs muscle and keeps you full. Carbohydrates are the body’s quickest fuel, especially for hard training. Fat supports hormones and helps you absorb vitamins. Knowing only your total calories is not enough for many goals. Two diets at 2,000 calories can feel very different if one has 60 grams of protein and the other has 150 grams.
The calculator turns your percentages into grams, which is how food labels and tracking apps report macros. It uses two simple facts: protein and carbohydrates each give 4 calories per gram, and fat gives 9 calories per gram. So at 2,000 calories, a split of 30 percent protein, 40 percent carbohydrates, and 30 percent fat gives 150 grams of protein, 200 grams of carbohydrates, and about 67 grams of fat. If your percentages do not add to 100, the tool warns you, so you can fix the split before you use it.
How to Use It
Type your daily calorie target first. If you do not have one, use our daily calorie calculator to estimate it. Then type your target percentages for protein, carbohydrates, and fat. Make sure they add to 100. Click Calculate. You will see grams and calories for each macro. A common starting split for general fitness is 30 percent protein, 40 percent carbohydrates, and 30 percent fat. Endurance athletes often raise carbohydrates. People who want to feel fuller often raise protein. There is no single split that works for everyone.
Choosing Your Split
Protein deserves attention first. A widely used guide is about 1.6 to 2.2 grams of protein per kilogram of body weight per day for people who train, and about 1.2 to 1.6 grams for active adults who do not lift heavily. For a 70-kilogram person, that is roughly 112 to 154 grams. Fill the rest with carbohydrates and fat based on what you enjoy and how you train. If you do long runs or play team sports, carbohydrates help performance. If you prefer richer food and smaller meals, a little more fat may suit you better. Keep the split flexible and change it if hunger or energy becomes a problem.
A Worked Example
Suppose you eat 2,400 calories a day and choose 30 percent protein, 45 percent carbohydrates, and 25 percent fat. Protein is 720 calories, which divided by 4 gives 180 grams. Carbohydrates are 1,080 calories, which divided by 4 gives 270 grams. Fat is 600 calories, which divided by 9 gives about 67 grams. In practice you will not hit these numbers exactly every day, and that is fine. Aim to land within about 10 grams of each target most days. Weekly averages matter more than any single meal.
Common Mistakes
The most common mistake is a split that does not add to 100 percent, which silently breaks the math. Another is setting protein too low while trying to lose weight, which can cost muscle along with fat. A third is cutting fat too far: below about 20 percent of calories, hormones and vitamin absorption can suffer. Finally, do not chase perfect numbers while eating almost no vegetables. Macros describe energy, but they say nothing about fibre, vitamins, or food quality. Build meals around whole foods first, then fit the macros.
Frequently Asked Questions
Do I have to weigh food? Weighing for a few weeks teaches you what portions really look like. After that, many people estimate well enough. Can I change my split on rest days? Yes. Some people eat more carbohydrates on training days and a little more fat on rest days. Keep protein steady. Is a high-protein diet safe? For healthy adults, the ranges above are widely used. If you have kidney disease or another medical condition, ask your doctor before raising protein.
Educational estimate only. This is not medical advice. Talk to a health professional before changing your diet, especially if you have a medical condition or take medication.
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- Calculadora de Macronutrientes (Spanish version)
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