How many grams of protein should I eat a day?

It depends on your calorie target and chosen split, but a common range is roughly 1.6–2.2 g of protein per kilogram of body weight for people who exercise regularly. Check the grams this calculator gives against that range for a sanity check.

Why are fat grams so much lower than protein or carb grams for the same percentage?

Fat has more than double the calories per gram (9 kcal/g) compared with protein and carbs (4 kcal/g each), so the same percentage of your daily calories works out to fewer grams of fat.

Do I need to hit my macros exactly every day?

No. Getting close on most days matters far more than precision on any single day. Total weekly calories and protein intake tend to matter most for body composition.

Which macro split is best for losing weight?

Any split can work for weight loss, since the calorie total does the heavy lifting. A higher-protein split is often preferred because protein is filling and helps preserve muscle while eating fewer calories.

Where do the calorie numbers come from?

From the Mifflin-St Jeor equation, using your height, weight, age, sex and activity level — the same formula used by this site's calorie calculator.

Macro Calculator: Protein, Carbs & Fat

Multiply your daily calorie target by each macro's percentage, then divide by its calories per gram: protein and carbs are 4 kcal/g, fat is 9 kcal/g. On a 2,000-calorie, 30/40/30 split, that's 150 g protein, 200 g carbs and 67 g fat.

Sex (used by the calorie formula)

Age (15–100)

years

Height

Weight

Activity level

Macro split

Daily calorie target

1,996 kcal

Protein

150g

599 kcal

Carbs

200g

798 kcal

Fat

67g

599 kcal

Calories come from the Mifflin-St Jeor equation, the same estimate used by the calorie calculator. Treat the grams as a starting point to adjust from, not an exact prescription.

Show the math

1
Work out your basal metabolic rate (BMR)
10 × 70 + 6.25 × 170 − 5 × 30 − 161 = 1,452
This is the Mifflin-St Jeor equation. BMR is the energy your body burns at complete rest to keep you alive.
= 1,452 kcal

Read the steps as text

Work out your basal metabolic rate (BMR). 10 × 70 + 6.25 × 170 − 5 × 30 − 161 = 1,452 This is the Mifflin-St Jeor equation. BMR is the energy your body burns at complete rest to keep you alive.
Multiply by your activity level. 1,452 × 1.375 (lightly active) = 1,996 Movement and exercise add to the energy you use each day. The result is your total daily energy expenditure (TDEE).
Adjust for your goal. Lose: 1,996 − 500 = 1,496 · Gain: 1,996 + 500 = 2,496 About 7,700 calories equals 1 kg of body weight, so a daily change of 500 calories is roughly 0.5 kg a week.
Split your calories by percentage. 1,996 kcal × 30% protein, 40% carbs, 30% fat Each macronutrient gets a share of your daily calorie target.
Convert protein calories to grams. 599 kcal ÷ 4 kcal/g = 150 g Protein and carbohydrate both provide about 4 calories per gram.
Convert carb calories to grams. 798 kcal ÷ 4 kcal/g = 200 g
Convert fat calories to grams. 599 kcal ÷ 9 kcal/g = 67 g Fat is more energy-dense, at about 9 calories per gram.

From calories to grams

"Macros" is short for macronutrients: protein, carbohydrate and fat, the three nutrients that provide calories (alcohol is sometimes counted as a fourth, at 7 kcal/g). This calculator first estimates your daily calorie need with the Mifflin-St Jeor equation, the same one used by the calorie calculator, then splits that number into grams using whichever ratio you choose.

Protein and carbohydrate each provide about 4 calories per gram, while fat provides about 9, more than double. That's why a 30% share of calories for fat translates into fewer grams than a 30% share for protein or carbs.

Choosing a split

A balanced 30/40/30 split (protein/carbs/fat) suits general health and fits most diets without much restriction. A lower-carb split reduces bread, rice, pasta and sugar in favour of more fat. A higher-protein split is common when building or preserving muscle, especially during weight loss, since protein helps protect lean mass. An endurance split leans on carbohydrate to fuel long training sessions and refill glycogen stores.

There's no single correct ratio — total calories matter more for weight change, and macro splits are mainly a tool for managing hunger, training performance and food preferences.

Using the numbers day to day

Treat the grams as a daily target to aim near, not a number to hit exactly. Protein sources include meat, fish, eggs, dairy, legumes and tofu; carbohydrate sources include grains, fruit, starchy vegetables and sugar; fat sources include oils, nuts, seeds, dairy fat and fatty meat or fish. Most whole foods are a mix of more than one macro, so a food tracking app makes it easier to see how a day of eating adds up against the targets here.

Frequently asked questions

How many grams of protein should I eat a day?: It depends on your calorie target and chosen split, but a common range is roughly 1.6–2.2 g of protein per kilogram of body weight for people who exercise regularly. Check the grams this calculator gives against that range for a sanity check.
Why are fat grams so much lower than protein or carb grams for the same percentage?: Fat has more than double the calories per gram (9 kcal/g) compared with protein and carbs (4 kcal/g each), so the same percentage of your daily calories works out to fewer grams of fat.
Do I need to hit my macros exactly every day?: No. Getting close on most days matters far more than precision on any single day. Total weekly calories and protein intake tend to matter most for body composition.
Which macro split is best for losing weight?: Any split can work for weight loss, since the calorie total does the heavy lifting. A higher-protein split is often preferred because protein is filling and helps preserve muscle while eating fewer calories.
Where do the calorie numbers come from?: From the Mifflin-St Jeor equation, using your height, weight, age, sex and activity level — the same formula used by this site's calorie calculator.