Macros are not a separate diet system. They're just your calorie target broken into three pieces: protein, carbohydrate, and fat. Once you know your TDEE and your goal, setting macros is a short sequence of steps that always runs in the same order. Get the order right and the numbers fall into place.
"Macros" is short for macronutrients: the three nutrients your body needs in large amounts and that supply energy. Protein, carbohydrate, and fat are the only things in food that carry calories (alcohol does too, but it isn't a nutrient your body needs). Every calorie you eat comes from one of them.
This means your macros and your calories are the same information viewed two ways. If you add up the calories from your protein, carb, and fat grams, you get your daily calorie total. So calculating macros is really just deciding how to divide a calorie target you've already set. You never set macros in a vacuum; you set them inside a calorie budget.
Each macronutrient carries a fixed amount of energy per gram. These four numbers are the entire conversion system between grams and calories, and they never change.
| Macronutrient | Calories per gram | Role |
|---|---|---|
| Protein | 4 | Builds and repairs muscle; high satiety |
| Carbohydrate | 4 | Primary training and brain fuel |
| Fat | 9 | Hormones, cell membranes, vitamin absorption |
| Alcohol | 7 | Energy only; no nutritional requirement |
Fat is the densest at 9 calories per gram, more than double protein or carbs. That's why a tablespoon of oil quietly carries 120 calories while a tablespoon of sugar carries about 50. To convert grams to calories, multiply by the number above. To convert calories to grams, divide.
Macros are set in a fixed sequence. Each step depends on the one before it, so do them in order.
Step 1 — Set calories. Start from your TDEE, then adjust for your goal: subtract 250–500 to cut, add 250–500 to bulk, or leave it as-is to maintain. This single number is your budget; everything else fits inside it.
Step 2 — Set protein. Protein comes first among the three macros because it's the one with a hard target. Use 0.7–1.0 grams per pound of body weight, leaning higher when you're lean or in a deficit. Multiply your grams by 4 to see how many calories protein uses.
Step 3 — Set fat. Fat has a floor you shouldn't drop below for hormone health. Use roughly 0.3–0.4 grams per pound, or 20–30% of total calories, whichever you prefer. Multiply your grams by 9 for its calorie cost.
Step 4 — Carbs fill the remainder. Subtract your protein and fat calories from your total. Whatever is left is your carb budget. Divide that leftover number by 4 to get carb grams. Carbs are the flexible macro that absorbs the rest of the calories.
You can't set macros without a calorie number. The calculator gives you TDEE plus five goal targets in seconds.
Calculate My Target →Let's run the steps for a 170-pound person whose TDEE is 2,600 calories and who wants to lose fat. We'll set a cut at 500 calories below TDEE.
Step 1 — Calories: 2,600 − 500 = 2,100 calories.
Step 2 — Protein: 170 lb × 1.0 g/lb = 170 g protein. At 4 cal/g that's 680 calories.
Step 3 — Fat: 170 lb × 0.35 g/lb ≈ 60 g fat. At 9 cal/g that's 540 calories.
Step 4 — Carbs: 2,100 − 680 − 540 = 880 calories left for carbs. At 4 cal/g that's 220 g carbs.
| Macro | Grams | Calories | % of total |
|---|---|---|---|
| Protein | 170 g | 680 | 32% |
| Fat | 60 g | 540 | 26% |
| Carbs | 220 g | 880 | 42% |
| Total | — | 2,100 | 100% |
The calorie columns add to exactly 2,100, which is the entire point. If your three macros don't sum back to your target, you've made an arithmetic slip somewhere. Round grams to the nearest 5 in practice; the body doesn't notice single-gram precision.
The step order never changes, but the inputs do. The two things that move are your calorie total (step 1) and where you sit inside the protein range (step 2).
On a cut, calories drop, so the carb remainder shrinks. Protein goes to the top of the range (closer to 1.0 g/lb) to protect muscle and keep you full while eating less. Fat stays near its floor. The net effect is a higher protein percentage and fewer carbs than at maintenance.
On a bulk, calories rise, and almost all of the extra goes to carbs because they fuel the training that drives growth. Protein can sit slightly lower in the range (0.7–0.8 g/lb is plenty in a surplus) since muscle retention isn't under threat. Fat holds steady. The result is a carb-heavy split with protein and fat anchored.
Notice that protein grams stay relatively stable across goals; it's carbs that expand and contract to track your calorie target. That's exactly what you'd expect from the "carbs fill the remainder" rule.
People grab a ratio like "40/30/30" off the internet and start tracking without ever pinning down a calorie number. A ratio is meaningless until you know the total it's a percentage of. Always set calories first.
Cutting fat below about 0.3 g/lb to "save room" for carbs can blunt hormone production over time. Protect the fat floor even when calories are tight.
The percentages are an output, not a goal. Two people at the same calories with the same protein and fat will land on slightly different carb percentages, and both are correct.
No. Calories decide whether you gain, lose, or maintain weight. Macros decide the quality of that change: how much is muscle versus fat, how full you feel, and how well you train. Calories are the foundation; macros are the finish. Get calories right first.
There's no single best ratio because the right split depends on your body weight and goal, not a fixed percentage. If you set protein and fat by the gram targets above and let carbs fill the rest, you'll naturally land somewhere sensible, often around 30% protein, 25% fat, 45% carbs. Chase the gram targets, not the percentages.
No. Aim to land within about 5–10 grams of each target on most days. Protein is the one worth being most consistent with; carbs and fat can shift around each other freely as long as total calories stay on budget. Perfection isn't required for results.
Fiber is a carbohydrate and is already inside your carb total, so there's no need to count it separately; just aim for 25–35 g a day for digestion and fullness. Alcohol carries 7 calories per gram and those calories are real, so if you drink, account for them by trimming carbs or fat that day to stay within your total.
Start with your burn, then split it. Get your TDEE and goal targets, then run the four steps above.
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