Figuring out your macros means calculating how many grams of protein, carbohydrates, and fat you should eat each day based on your body, activity level, and goals. The process has three steps: estimate your daily calorie needs, choose a percentage split for each macronutrient, then convert those percentages into grams. Here’s how to do each one.
What Macros Actually Are
Macronutrients are the three categories of nutrients your body uses for energy. Protein and carbohydrates each provide 4 calories per gram, while fat provides 9 calories per gram. Every food you eat is some combination of these three, and “knowing your macros” means having a specific gram target for each one rather than just tracking total calories.
Why bother splitting calories into macros? Because where your calories come from affects how you feel, how you perform, and what kind of weight you gain or lose. Two people eating 2,000 calories a day can have very different body composition, energy levels, and hunger depending on their protein-to-carb-to-fat balance.
Step 1: Estimate Your Daily Calories
Before you can divide calories into macros, you need a reasonable estimate of how many calories your body burns in a day. This number is called your total daily energy expenditure (TDEE), and it starts with your resting metabolic rate (RMR), the calories your body uses just to stay alive.
The Mifflin-St Jeor equation is considered the most accurate formula for estimating RMR in adults. It uses your weight in kilograms, height in centimeters, and age in years:
- Men: (9.99 × weight) + (6.25 × height) − (4.92 × age) + 5
- Women: (9.99 × weight) + (6.25 × height) − (4.92 × age) − 161
To convert pounds to kilograms, divide by 2.2. To convert inches to centimeters, multiply by 2.54. For example, a 35-year-old woman who weighs 150 pounds (68 kg) and stands 5’6″ (167.6 cm) would calculate: (9.99 × 68) + (6.25 × 167.6) − (4.92 × 35) − 161, which comes out to roughly 1,400 calories at rest.
Next, multiply your RMR by an activity factor to get your TDEE:
- Sedentary (desk job, little exercise): RMR × 1.2
- Lightly active (exercise 1–3 days/week): RMR × 1.375
- Moderately active (exercise 3–5 days/week): RMR × 1.55
- Very active (hard exercise 6–7 days/week): RMR × 1.725
That same woman, if she exercises three times a week, would multiply 1,400 by 1.55 for a TDEE of about 2,170 calories. This is her maintenance number. To lose fat, she’d subtract 300 to 500 calories. To gain muscle, she’d add 200 to 300.
Step 2: Choose Your Macro Split
The Dietary Guidelines for Americans recommend broad ranges called Acceptable Macronutrient Distribution Ranges: 10–35% of calories from protein, 45–65% from carbohydrates, and 20–35% from fat. These ranges are wide on purpose, because the right split depends on your goal and how your body responds.
Research consistently shows there is no single ideal macro ratio. The most important factor for weight loss is eating fewer calories than you burn. That said, protein deserves special attention because it preserves muscle during a calorie deficit, keeps you fuller longer, and costs more energy to digest than carbs or fat. Most people benefit from setting protein first and then filling in carbs and fat around it.
Setting Protein First
Protein recommendations scale with how active you are. Sedentary adults need roughly 0.8 grams per kilogram of body weight per day, which is the minimum to maintain basic function. If you exercise regularly at moderate intensity, that number rises to 1.2–1.5 grams per kilogram. Strength athletes or anyone focused on building muscle should aim for 1.6–2.0 grams per kilogram.
For a 170-pound (77 kg) person who lifts weights three times a week, the target would be roughly 123–154 grams of protein per day. At 4 calories per gram, that’s 492–616 calories from protein alone.
Dividing Carbs and Fat
Once protein is set, split the remaining calories between carbohydrates and fat based on your preferences and activity type. People who do a lot of endurance or high-intensity exercise tend to perform better with more carbs (50–60% of total calories), because carbohydrates are the body’s preferred fuel during intense effort. People who prefer fattier foods, feel more satisfied with higher-fat meals, or do lower-intensity activity can shift toward 30–35% fat and fewer carbs.
A common starting point for someone who exercises regularly and wants to lose fat: 30% protein, 40% carbs, 30% fat. For someone focused on athletic performance or muscle gain: 25% protein, 50% carbs, 25% fat. These are starting points, not rules. Adjust based on how you feel after two to three weeks.
Step 3: Convert Percentages to Grams
This is where your macros become something you can actually track. Take the calorie amount for each macronutrient and divide by its calories per gram.
Here’s an example for someone eating 2,000 calories with a 30/40/30 split:
- Protein: 2,000 × 0.30 = 600 calories ÷ 4 = 150 grams
- Carbs: 2,000 × 0.40 = 800 calories ÷ 4 = 200 grams
- Fat: 2,000 × 0.30 = 600 calories ÷ 9 = 67 grams
Those three numbers (150g protein, 200g carbs, 67g fat) are your daily macro targets. Write them down, plug them into a tracking app, or use them as a rough mental guide when building meals.
Tracking Your Macros Day to Day
Most people track macros using a food logging app with a built-in nutrition database. You search for a food, enter the amount, and the app tallies your running totals. The databases behind these apps are large but imperfect. They can misidentify portion sizes, and they tend to underrepresent regional and cultural cuisines. Using a kitchen scale for staple foods like rice, meat, and oils dramatically improves accuracy compared to eyeballing portions.
You don’t need to hit your targets to the gram. Staying within 5–10 grams of each target on most days is close enough to see results. Protein is the macro worth being most precise about, because it has the strongest effect on satiety and muscle retention. If you’re going to be loose with any number, let it be the carb-to-fat ratio, which matters less than total calories and protein.
Signs Your Macros Need Adjusting
Your initial calculation is an educated guess. Your body will tell you whether it’s working within the first few weeks. Low energy during workouts usually signals that carbohydrates are too low, especially if you do high-intensity or endurance exercise. Constant hunger between meals, even when you’re eating enough total calories, often means protein or fat is too low, since both slow digestion and increase fullness. Feeling sluggish or mentally foggy can point to either insufficient total calories or too little carbohydrate, which is the brain’s primary fuel source.
On the results side, losing more than about 1% of your body weight per week suggests your deficit is too aggressive and you’re likely losing muscle along with fat. Gaining weight faster than about half a pound per week during a muscle-building phase means excess calories are being stored as fat. Adjustments should be small: add or subtract 100–200 calories at a time by shifting one macronutrient, then give it two weeks before evaluating again.
Your macros also aren’t fixed forever. As your weight changes, your calorie needs change. Recalculate every 10–15 pounds of weight change, or whenever your activity level shifts significantly, like starting a new training program or switching from a desk job to a more physical one.