Macronutrient calculator

What it's for

Counting calories isn't enough: how you split them between protein, carbs and fat (the «macros») matters. Here you get the breakdown in grams for your goal.

How it works

Protein and carbs give 4 kcal per gram, fat 9. The percentages apply to total calories, then convert to grams. Not medical advice.

What the three macronutrients actually do

Protein builds and repairs: muscle, skin, enzymes, antibodies. It is also the macronutrient that fills you up most for the same calories, which is why nearly every split designed for weight loss raises it. Carbs are the fast fuel: the brain alone burns around 120 grams a day, and they are the source muscle prefers when the effort is hard. Fat is not an enemy to cut to zero: it is what lets you absorb vitamins A, D, E and K and what hormones are made from, and below a certain share the body notices.

A percentage is not an amount

Thirty per cent protein is not an amount: it is a slice. On 1,500 kcal it comes to 112 grams, on 3,000 kcal to 225 grams, twice as much under the same label. That is why someone following a plan found online, with a calorie need different from the person who wrote it, ends up with numbers that look nothing like their own.

The reference most used for protein, in fact, is not a percentage but an amount per kilogram of body weight: people doing strength work usually sit between 1.6 and 2.2 grams per kilo. If the gram figure that comes out here is far outside that band, the number to revise is the percentage, not your weight.

Why the fat grams are always few

One gram of fat is worth nine kilocalories, more than double a gram of protein or carbs, which are worth four. So 30% of calories from fat is not 30% of the food on your plate: on 2,000 kcal it is 67 grams, against the 150 grams of protein that weigh the same in calories. Looking at the gram column and concluding that fat is a small part is a reading error: it is small by weight precisely because it is dense.

What this page does not do

It does not count the calories of what you eat: for that you need the label or a nutrition table. It knows nothing about food quality, and two days with the same macros can be very different from each other. And above all it is not a meal plan: illness, medication, pregnancy, breastfeeding and competitive sport change the picture, and there the split is a professional's call.

Nearby tools

The total calories to start from are estimated by Calorie needs and Basal metabolic rate; for a weight-loss goal there is Calorie deficit. The calories of individual foods are in Food calories.