Macro calculator: protein, carbs and fat in grams

How to calculate your macros

Macros, short for macronutrients, are protein, carbohydrate and fat. Each gram of protein or carbohydrate has about 4 calories and each gram of fat about 9. This calculator works out your macros in four steps:

1. Calories. Your TDEE from the Mifflin-St Jeor equation and your activity level, minus 500 calories to lose weight or plus 300 to build muscle, and never below 1,200 for women or 1,500 for men.
2. Protein is set first, in grams per kilogram of body weight, because it is the one with a clear target.
3. Fat or carbohydrate comes next, depending on the diet style: fat as a share of calories, or a fixed amount of carbohydrate for low-carb and keto.
4. The remaining macro takes whatever calories are left.

A worked example, at 1,800 calories and 160 lb (72.6 kg), balanced, losing weight: protein is 1.8 × 72.6 ≈ 131 g, which is 524 calories. Fat is 30 percent of 1,800 = 540 calories, or 60 g. Carbohydrate takes the rest: (1,800 − 524 − 540) ÷ 4 ≈ 184 g.

The four diet styles

• Balanced: protein at 1.6 g/kg (about 0.7 g per pound), or 1.8 g/kg (0.8 g/lb) when losing weight; fat at 30 percent of calories; carbohydrate takes the rest. Fat sits within the US Dietary Guidelines' 20 to 35 percent range; with protein set this high, carbohydrate can come out a little under their 45 percent.
• High protein: protein at 2.2 g/kg (1 g/lb) and fat at 25 percent. Useful in a deficit, where protein protects muscle and keeps hunger down.
• Low carb: carbohydrate held at about 100 g a day, protein at 1.8 g/kg, and fat taking the rest.
• Keto: about 25 g of total carbohydrate a day, protein at 1.6 g/kg, and the rest from fat.

Keto macros

The keto setting usually works out to 3 to 7 percent of calories from carbohydrate, 20 to 35 percent from protein, and the rest, roughly 55 to 80 percent, from fat. The exact split depends on how many calories you eat, because carbohydrate and protein are fixed in grams rather than as percentages. That is deliberate: ketosis depends on the amount of carbohydrate, not its share, and most people need to stay under about 20 to 50 g a day. There is more on how it works in what the keto diet is, and on the first week in keto flu.

If you take medication for diabetes or blood pressure, or have kidney disease, talk to your doctor before starting keto or a high-protein diet. Doses can need adjusting quickly.

What is the best macro ratio for weight loss?

The one you can keep. In metabolic-ward studies where calories and protein are matched, the split between carbohydrate and fat makes little difference to fat loss. Real-world trials agree: in DIETFITS, published in JAMA in 2018, 609 adults followed a healthy low-fat or a healthy low-carb diet for a year without counting calories. Both groups lost about the same, around 12 to 13 pounds on average, with a wide spread within each group.

So the order of importance is: calories first, protein second, and the split between carbohydrate and fat a distant third. Choose the style that suits the food you like to eat. Low-carb and keto help some people because they make it easier to eat less, not because they burn fat in a way other diets do not.

How much protein per meal

Total daily protein matters far more than timing. Spreading it across the day may help muscle a little: a common target, from a 2018 review by Schoenfeld and Aragon, is about 0.4 g per kilogram per meal over at least four meals, which is why the calculator defaults to four. With three meals, a protein-rich snack makes the fourth. Breakfast is where most people come up short, and the easiest to fix: eggs, Greek yogurt, cottage cheese, or a couple of protein balls alongside.

Why protein is capped for some people

Protein targets in grams per kilogram were developed in people of ordinary body composition. For someone carrying a lot of fat mass, total body weight overstates how much protein they need. Above a BMI of 30, this calculator therefore sets protein on the weight at a BMI of 30 for your height, so the target is not inflated by fat mass and never drops as weight rises past that line. For the full protein ranges by goal, see the protein calculator.

Counting macros vs counting calories

Counting macros is counting calories with more detail. It is useful if you want to hit a protein target or are following low-carb or keto. If you only want to lose weight, tracking calories and protein alone gets you most of the benefit with half the effort. Fiber is worth a glance too: most adults should get 25 to 35 g a day, and most Americans eat about half of that.