How to calculate your macros

Macros, short for macronutrients, are the three nutrients that provide your calories: protein, carbohydrates and fat. Working them out takes three steps.

Step 1: Find your daily calories

The calculator estimates your resting energy use (BMR) with the Mifflin-St Jeor equation, then multiplies it by an activity factor to get your maintenance calories (TDEE).

Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5

Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161

TDEE = BMR × Activity factor (1.2 for sedentary up to 1.9 for very active)

Your goal then shifts the total: about 500 kcal below TDEE for steady fat loss, or 250 to 500 kcal above for muscle and weight gain.

Step 2: Choose a split

Pick the share of calories that comes from each macro. A balanced split is 25% protein, 45% carbs and 30% fat. Higher protein is common for fat loss and strength training, and lower carb or keto splits move calories from carbs to fat.

Step 3: Convert percentages to grams

Each gram of a macro contains a set number of calories:

Protein: 4 kcal per gram
Carbohydrates: 4 kcal per gram
Fat: 9 kcal per gram

Grams = Daily calories × Share of calories ÷ Calories per gram

Worked example

A 30-year-old man, 70 kg, 170 cm, moderately active, who wants to lose weight with a high protein split (35% protein, 35% carbs, 30% fat):

BMR = 10 × 70 + 6.25 × 170 − 5 × 30 + 5 = 1,617.5 kcal
TDEE = 1,617.5 × 1.55 = 2,507 kcal
Target = 2,507 − 500 = 2,007 kcal a day
Protein = 2,007 × 35% ÷ 4 = 176 g
Carbs = 2,007 × 35% ÷ 4 = 176 g
Fat = 2,007 × 30% ÷ 9 = 67 g

That protein works out to about 2.5 g per kg of body weight, or 1.1 g per pound.

How much protein do you need?

Most guidance for active people falls between 1.2 and 2.2 g of protein per kg of body weight (about 0.5 to 1 g per pound). The calculator shows your protein per kg so you can check that your split lands in a sensible range, especially when you are eating fewer calories.

How to use the macro calculator

Enter your details. Choose metric or imperial, then add your sex, age, weight and height.
Pick your activity level. Be honest. Counting only planned workouts gives a more accurate figure than guessing how active you feel.
Choose a goal. Select weight loss, maintenance or gain. The calculator adjusts your daily calories for you.
Choose a macro split. Start with balanced or high protein. Select Custom split to enter your own protein and carb percentages, and fat fills the rest.
Read your targets. You will see your daily calories, the grams of protein, carbs and fat, and a breakdown table. Open Advanced options to see the grams per meal.

Treat the numbers as a starting point. Track your weight and energy for two to three weeks, then change calories by 100 to 200 a day if the result is not what you want. If you have a medical condition, are pregnant or have a history of disordered eating, check with a doctor or registered dietitian first.

Frequently Asked Questions

How do I calculate my macros?

First estimate your daily calories (BMR times an activity factor, then adjusted for your goal). Next choose what share of those calories comes from protein, carbs and fat. Finally divide each share by its calories per gram: 4 for protein and carbs, 9 for fat. The calculator does all three steps for you.

What is a good macro split for weight loss?

Many people do well with a higher protein split such as 35% protein, 35% carbs and 30% fat, because protein is filling and helps preserve muscle in a calorie deficit. The most important factor is the calorie deficit itself, so pick a split you can follow consistently.

How many grams of protein should I eat per day?

The general minimum is 0.8 g per kg of body weight. People who exercise regularly or are losing fat often aim for 1.2 to 2.2 g per kg (about 0.5 to 1 g per pound). The results panel shows your protein per kg so you can compare.

How many calories are in a gram of protein, carbs and fat?

Protein and carbohydrates each provide about 4 calories per gram, and fat provides about 9 calories per gram. Alcohol provides about 7 calories per gram but is not counted as a macro here.

Is a macro calculator accurate?

It gives a reliable starting estimate, not an exact prescription. The Mifflin-St Jeor equation is accurate for most adults within about 10%, and real needs vary with muscle mass, genetics and daily movement. Adjust your calories after a few weeks of tracking.

What macros should I eat to build muscle?

Choose the muscle gain goal for a small calorie surplus, and keep protein around 1.6 to 2.2 g per kg of body weight. The rest of your calories can come from carbs and fat in whatever balance you prefer, with carbs fuelling harder training.

How is a keto macro split different?

A ketogenic split keeps carbs very low, usually 5% of calories or under 50 g a day, and gets most calories from fat. The keto option here uses 20% protein, 5% carbs and 75% fat. Talk to a doctor before starting keto if you have a health condition or take medication.

Related Calculators

Calorie Calculator (TDEE & BMR)

Estimate your daily calorie needs, BMR and TDEE, and the calories to eat to lose, maintain or gain weight

Water Intake Calculator

Estimate how much water to drink each day from your weight, exercise, climate and pregnancy or breastfeeding, in liters, ounces and cups

Ideal Weight Calculator

Calculate your Ideal Body Weight (IBW) based on height and gender using standard medical formulas

Body Fat Calculator (US Navy Method)

Estimate your body fat percentage from height, neck, waist and hip measurements using the US Navy tape-measure method

Macro Calculator