What are macros?
Macros are the three macronutrients your body needs in large amounts: protein (builds and repairs muscle), carbohydrates (the body's main quick energy source) and fat (supports hormones and absorbs vitamins). Protein and carbohydrates give 4 calories per gram; fat gives 9 calories per gram.
Calculating your macros means turning your body, activity and goal into three daily numbers: grams of protein, grams of carbs and grams of fat. Here is how, in 6 steps.
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Calculate your BMR
Your BMR (basal metabolic rate) is the calories you burn at complete rest. It is estimated with the Mifflin-St Jeor equation from your age, weight, height and gender.
Try it: BMR Calculator →
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Find your TDEE with an activity multiplier
Multiply your BMR by an activity factor to get TDEE (total daily energy expenditure) — the calories you burn on a normal day:
Activity level Multiplier Sedentary (little exercise) 1.2 Light (1–3 days/week) 1.375 Moderate (3–5 days/week) 1.55 Active (6–7 days/week) 1.725 Very active (physical job / twice daily) 1.9 Try it: TDEE Calculator →
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Set your goal calories
Adjust your TDEE for your goal. Common starting points:
- Lose weight: TDEE − 500 kcal per day
- Maintain weight: TDEE (no change)
- Gain muscle: TDEE + 300 kcal per day
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Set your protein from body weight
Protein is set from body weight, not from calories. Active people usually need about 1.6 to 2.2 grams of protein per kilogram of body weight per day. For a 75 kg active person that is roughly 120 to 165 g of protein daily.
Try it: Protein Calculator →
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Set your fat as a share of calories
Fat is usually set as 20–35% of your goal calories. Divide those calories by 9 to get grams (fat gives 9 kcal per gram). For example, 30% of 2,633 kcal is 790 kcal of fat, which is about 88 g.
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Fill the rest with carbs
Whatever calories remain after protein and fat go to carbohydrates. Divide by 4 to get grams (carbs give 4 kcal per gram). This is why the Macro Calculator shows protein 30%, carbs 40% and fat 30% — the carbs simply fill what is left.
Worked example
A 30-year-old man, 75 kg, 175 cm, moderately active, maintaining weight:
- Step 1 — BMR: about 1,699 kcal (Mifflin-St Jeor)
- Step 2 — TDEE: 1,699 × 1.55 = about 2,633 kcal
- Step 3 — Goal: maintain, so 2,633 kcal (weight loss would be 2,133 kcal; muscle gain 2,933 kcal)
- Steps 4–6 — Macros: about 197 g protein, 263 g carbs and 88 g fat per day
Want your own numbers? Use the Lean Body Mass Calculator too — knowing your lean mass helps you fine-tune protein.
Frequently Asked Questions
What are macros? Macros are the three macronutrients: protein, carbohydrates and fat. Protein and carbohydrates give 4 calories per gram, fat gives 9 calories per gram.
How do I calculate my macros step by step? First find your BMR, then multiply by an activity factor to get TDEE, adjust for your goal (lose, maintain or gain), set protein from body weight, set fat as a share of calories, and fill the remaining calories with carbohydrates.
How many calories should I eat to lose weight? A common starting point is TDEE minus 500 kcal per day, which is a steady deficit for most adults. For muscle gain, TDEE plus 300 kcal is a common starting point.
How much protein do I need per day? Active people usually need about 1.6 to 2.2 grams of protein per kilogram of body weight per day. For a 75 kg active person that is roughly 120 to 165 g of protein daily.
Do I need to hit my macros exactly every day? No. Daily totals matter most, and small day-to-day variation is normal. Consistency over weeks matters more than one perfect day.
Is this medical advice? No. This is general information only. Talk to a doctor or registered dietitian before changing your diet, especially if you have a health condition.