Calculating your macros means figuring out how many grams of protein, carbohydrates, and fat you should eat each day based on your calorie needs 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.
Step 1: Estimate Your Daily Calories
Your daily calorie target starts with your basal metabolic rate (BMR), the number of calories your body burns just to stay alive. The most widely used formula is the Mifflin-St Jeor equation:
- Men: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
- Women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
If you use pounds, divide your weight by 2.2 to get kilograms. For inches, multiply by 2.54 to get centimeters. As an example, a 35-year-old woman who weighs 150 pounds (68 kg) and stands 5’6″ (167.6 cm) would calculate: (10 × 68) + (6.25 × 167.6) – (5 × 35) – 161 = 1,393 calories.
That number only covers basic survival. To account for how much you move, multiply it by an activity factor:
- Sedentary (desk job, no exercise): BMR × 1.2
- Lightly active (exercise 1 to 3 days per week): BMR × 1.375
- Moderately active (exercise 3 to 5 days per week): BMR × 1.55
- Very active (hard exercise 6 to 7 days per week): BMR × 1.725
- Extremely active (intense training plus physical job): BMR × 1.9
The result is your total daily energy expenditure, or TDEE. Our example woman with a moderately active lifestyle would land around 2,159 calories (1,393 × 1.55). That’s her maintenance number. To lose fat, subtract 300 to 500 calories. To gain muscle, add 200 to 300.
Step 2: Choose Your Macro Split
The Dietary Guidelines for Americans recommend 45 to 65% of calories from carbohydrates, 10 to 35% from protein, and 20 to 35% from fat. Those ranges are broad on purpose. Where you land within them depends on your goal.
For fat loss, a higher protein intake helps you retain muscle while eating fewer calories. Research suggests 1.2 to 2.0 grams of protein per kilogram of body weight is beneficial for weight loss and muscle retention. That’s noticeably higher than the baseline recommendation of 0.8 grams per kilogram for sedentary adults. A common fat loss split looks like 30% protein, 35% carbs, and 35% fat, though the exact numbers matter less than consistently hitting a higher protein target.
For muscle gain, protein stays high (around 1.6 grams per kilogram for people training intensely), but carbohydrates also go up to fuel workouts and recovery. A typical split might be 25 to 30% protein, 40 to 50% carbs, and 20 to 30% fat. For general health or maintenance with moderate exercise, something like 30% protein, 40% carbs, and 30% fat works as a reasonable starting point. None of these splits are rigid rules. They’re frameworks you adjust based on how you feel, perform, and progress.
Step 3: Convert Percentages to Grams
Each macronutrient carries a different calorie load per gram. Protein has 4 calories per gram, carbohydrates have 4 calories per gram, and fat has 9 calories per gram. This is where the actual math happens.
Let’s say your target is 2,000 calories with a 30/40/30 split (protein/carbs/fat):
- 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 are your daily targets. You can also work backward if you already know your protein goal in grams. If you weigh 75 kg and want 1.6 grams per kilogram, that’s 120 grams of protein (480 calories). Subtract those calories from your total, then split the remainder between carbs and fat using whatever ratio suits you.
Tracking Accurately With a Food Scale
The most common tracking mistake is measuring food by volume instead of weight. A cup of flour scooped loosely can weigh 85 grams, while the same cup packed firmly can hit 170 grams, doubling the calories. Peanut butter, rice, oats, and nuts are especially easy to underestimate with measuring cups or spoons. A digital kitchen scale removes the guesswork for around $10 to $15.
Meat is another common source of error. Most nutrition labels list values for raw meat, but cooking drives off moisture and concentrates the calories. A beef steak loses roughly 24 to 25% of its weight during cooking. If you weigh your steak after cooking and log it using the raw entry in your tracking app, you’ll undercount by a significant margin. The simplest fix is to always weigh meat raw, or use the “cooked” entry in your app if you weigh it after cooking.
How to Handle Alcohol
Alcohol contains 7 calories per gram, sitting between carbs and fat in calorie density. Most tracking apps don’t have a dedicated alcohol macro category, so you need to borrow from your carb or fat budget. The easiest method: take the total calories in your drink and divide by 4 to count it as carbs, or divide by 9 to count it as fat. A 150-calorie glass of wine, for instance, would cost you either 37.5 grams of carbs or about 17 grams of fat. You can also split it between both. Either way, the calories get accounted for.
Net Carbs vs. Total Carbs
If you follow a lower carb approach, you may want to track net carbs rather than total carbs. Fiber passes through your body without being fully absorbed, so many people subtract it: total carbs minus fiber equals net carbs. Sugar alcohols (common in protein bars and sugar-free products) are partially absorbed. The standard approach is to subtract half the sugar alcohol grams from your total carbs. A bar with 29 grams of total carbs and 18 grams of sugar alcohols would count as 20 grams of net carbs.
Adjusting Over Time
Your first set of macro targets is an educated guess. Give any new set of numbers at least two to three weeks before making changes, because daily weight fluctuations from water, sodium, and digestion can mask real trends. If you’re trying to lose fat and the scale hasn’t budged after three weeks of consistent tracking, reduce your total calories by 100 to 200 per day, pulling mainly from carbs or fat while keeping protein steady.
If your energy in the gym drops noticeably, carbs are likely too low. If you’re always hungry, try shifting some carb calories toward protein or fat, both of which tend to keep you fuller. Your macros aren’t a permanent prescription. They’re a starting point you refine as your body, activity level, and goals change.