Calculating your macros means figuring out 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 how many calories you burn, decide what you’re trying to achieve, then split those calories across the three macronutrients. Here’s how to do each one.
Step 1: Estimate Your Daily Calories
Before you can split calories into macros, you need to know roughly how many calories your body uses in a day. This number is called your Total Daily Energy Expenditure (TDEE), and you get it by first calculating your Basal Metabolic Rate (BMR), the energy your body burns just to stay alive, then adjusting for how active you are.
The most widely recommended formula is the Mifflin-St Jeor equation. You’ll need your weight in kilograms, height in centimeters, and age in years. To convert pounds to kilograms, divide by 2.2. To convert inches to centimeters, multiply by 2.54.
- For men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- For women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
So a 35-year-old woman who weighs 70 kg (154 lbs) and stands 165 cm (5’5″) tall would calculate: (10 × 70) + (6.25 × 165) − (5 × 35) − 161 = 700 + 1031 − 175 − 161 = 1,395 calories. That’s her BMR, the baseline before activity is factored in.
Step 2: Factor In Your Activity Level
Multiply your BMR by the number that best matches your typical week:
- Sedentary (desk job, little exercise): BMR × 1.2
- Lightly active (light exercise 1–3 days per week): BMR × 1.375
- Moderately active (moderate exercise 3–5 days per week): BMR × 1.55
- Very active (hard exercise 6–7 days per week): BMR × 1.725
- Extremely active (intense training twice daily or hard physical labor): BMR × 1.9
Using the example above, if that woman exercises moderately three to five days a week, her TDEE would be 1,395 × 1.55 = roughly 2,162 calories per day. Most people overestimate their activity level, so if you’re unsure, pick the lower option. You can always adjust after a few weeks based on real results.
Step 3: Adjust Calories for Your Goal
Your TDEE is a maintenance number, meaning it keeps your weight roughly the same. To change your body composition, you adjust from there.
For fat loss, cutting about 500 calories per day from your TDEE typically produces about half a pound to one pound of loss per week. Larger deficits can work short-term but tend to be harder to sustain and may cost you muscle. For muscle gain, adding 250 to 500 calories above maintenance gives your body the extra energy it needs to build tissue without excessive fat gain. If you want to maintain your current weight, your TDEE is your target.
Continuing the example: if our 2,162-calorie woman wants to lose fat, her adjusted target would be around 1,662 calories per day.
Step 4: Set Your Protein Target
Protein is the macro most worth getting right, because it drives muscle repair, keeps you full, and burns the most energy during digestion (your body uses 15 to 30% of protein calories just breaking it down, compared to 5 to 10% for carbs and 0 to 3% for fat).
The baseline recommendation for sedentary adults is 0.8 grams of protein per kilogram of body weight. That’s enough to prevent deficiency, but most people tracking macros want more. Endurance athletes do well with 1.2 to 1.4 grams per kilogram. Strength and power athletes benefit from 1.4 to 1.8 grams per kilogram. If you’re in a calorie deficit, staying toward the higher end of these ranges helps preserve muscle.
For our 70 kg woman who lifts weights a few times per week, a target of 1.6 g/kg gives her 112 grams of protein per day. Since protein provides 4 calories per gram, that’s 448 calories from protein.
Step 5: Set Your Fat Target
Dietary fat is essential for hormone production and absorbing fat-soluble vitamins. The Dietary Guidelines for Americans recommend that 20% to 35% of your total calories come from fat. The World Health Organization suggests capping fat at 30% of total energy. A good starting point for most people is 25% to 30%.
Using 25% for our example: 1,662 total calories × 0.25 = 415 calories from fat. Fat provides 9 calories per gram, so that’s about 46 grams of fat per day. Going below roughly 20% of total calories from fat can interfere with hormone function and make meals feel unsatisfying, so treat that as a practical floor.
Step 6: Fill the Rest With Carbohydrates
Carbohydrates get whatever calories remain after protein and fat are accounted for. This isn’t because carbs are less important. They’re your body’s preferred fuel for exercise and brain function. It’s just that protein and fat have physiological minimums that matter more to set first.
In our example: 1,662 total calories − 448 protein calories − 415 fat calories = 799 calories from carbohydrates. At 4 calories per gram, that’s about 200 grams of carbs per day.
Within your carbohydrate target, aim for about 14 grams of fiber per 1,000 calories you eat. For a 1,662-calorie diet, that’s roughly 23 grams of fiber daily. Fiber supports digestion, blood sugar stability, and long-term health, and most Americans fall well short of recommended amounts.
The Final Macro Split
Here’s how our full example looks in one place, for a 70 kg moderately active woman eating 1,662 calories to lose fat:
- Protein: 112 g (448 calories, 27% of total)
- Fat: 46 g (415 calories, 25% of total)
- Carbohydrates: 200 g (799 calories, 48% of total)
Your numbers will differ based on your body, goals, and preferences. Someone focused on building muscle at a calorie surplus would have higher carbs and total calories. Someone who prefers a higher-fat eating style might push fat to 30 or 35% and reduce carbs accordingly. The math is the same either way: set protein first, choose a fat percentage, and let carbs fill the gap.
Total Carbs vs. Net Carbs
If you track carbs using food labels, you’ll notice a “total carbohydrate” number that includes starch, sugar, and fiber. Some people subtract fiber and sugar alcohols to get “net carbs,” the idea being that fiber isn’t fully absorbed. The reality is more nuanced. Some fibers and sugar alcohols are partially digested, still providing calories and affecting blood sugar. The FDA recommends using total carbohydrates, and the American Diabetes Association echoes that advice, noting that the net carb equation isn’t entirely accurate because different fibers behave differently. For most people tracking macros, sticking with total carbs is simpler and more reliable.
Tips for Accurate Tracking
A food scale is the single most useful tool. Eyeballing portions can be off by 30% or more, especially for calorie-dense foods like nuts, oils, and cheese. Weigh foods in grams rather than using cup measurements when possible, since density varies. Log ingredients before cooking rather than after, because water loss during cooking changes the weight of food without changing its calorie content.
Treat your initial macro targets as a starting point, not a prescription. Track for two to three weeks, then assess. If you’re trying to lose weight and the scale isn’t moving, your TDEE estimate may be slightly high, and dropping 100 to 200 calories (usually from carbs or fat) is a reasonable adjustment. If you’re gaining weight faster than expected on a surplus, pull back slightly. The formulas give you a solid estimate, but your body provides the real data.