How to calculate your macros — protein, carbs and fat targets explained

📅 May 2026⏱ 6 min read🏷 Nutrition

Macronutrients — protein, carbohydrates and fat — are the three categories of nutrients that provide your body with energy. Tracking macros is a step beyond just counting calories: instead of hitting a single daily number, you hit targets for each macronutrient. This matters because 2,000 calories of protein, fat and carbs in different ratios produces very different results in terms of body composition, energy and performance.

What each macro does

Protein (4 kcal per gram) — builds and repairs muscle tissue, keeps you full, supports immune function and hormone production. Inadequate protein makes it harder to maintain muscle while losing fat.
Carbohydrates (4 kcal per gram) — the body's preferred energy source, especially for the brain and during high-intensity exercise. Not the enemy — the type and timing matters more than the total.
Fat (9 kcal per gram) — essential for hormone production (including testosterone and oestrogen), fat-soluble vitamin absorption (A, D, E, K), and brain health. Fat is calorie-dense but essential — cutting it too low causes hormonal problems.

Step 1 — Find your total daily energy expenditure (TDEE)

Before setting macro targets you need to know how many total calories you need. TDEE = your Basal Metabolic Rate (the calories you'd burn doing nothing) multiplied by an activity factor.

Calculate your BMR using the Mifflin-St Jeor equation:

Men: (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5
Women: (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161

Multiply BMR by your activity level:
Sedentary (desk job, little exercise) × 1.2
Lightly active (1–3 days/week exercise) × 1.375
Moderately active (3–5 days/week) × 1.55
Very active (hard exercise 6–7 days) × 1.725

The result is your TDEE — the calories needed to maintain your current weight. Eat less to lose fat, eat more to gain muscle.

Step 2 — Set your calorie target

Fat loss: subtract 300–500 calories from TDEE. A 500-calorie deficit loses approximately 0.5 kg (1 lb) per week.
Muscle gain: add 200–300 calories to TDEE (a lean bulk). Larger surpluses mostly add fat.
Maintenance/recomposition: eat at TDEE. Body recomposition (losing fat while gaining muscle) is possible, especially for beginners.

Step 3 — Set your macro ratios

Goal	Protein	Carbs	Fat
Fat loss	35–40%	30–40%	20–30%
Muscle gain	25–30%	45–50%	20–25%
General health	20–30%	40–50%	25–35%
Keto (low carb)	25–30%	5–10%	60–70%

These are starting points, not rules. Many people do well with different splits. The most important number is protein — get that right first, then fill remaining calories with carbs and fat in whatever ratio feels sustainable.

Step 4 — Convert percentages to grams

Example: TDEE is 2,200 calories, goal is fat loss, protein target is 35%.

Protein: 2,200 × 0.35 = 770 calories ÷ 4 = 192g protein
Carbs (35%): 2,200 × 0.35 = 770 calories ÷ 4 = 192g carbs
Fat (30%): 2,200 × 0.30 = 660 calories ÷ 9 = 73g fat

Protein: the priority macro

Most nutrition research suggests 1.6–2.2g of protein per kg of bodyweight as the optimal range for people who exercise. At 80 kg, that's 128–176g per day. Higher protein is particularly important when in a calorie deficit — it protects muscle mass and keeps you full. For most people, getting protein right matters more than perfect carb and fat splits.

💪 Calculate Your Macros

Enter your details and get your personalised protein, carb and fat targets instantly.

Open Macro Calculator →

Common macro tracking mistakes

Not tracking cooking oils and sauces — a tablespoon of olive oil is 120 calories and 14g fat. These add up invisibly.
Weighing food cooked instead of raw — chicken loses about 25% of its weight when cooked. Weigh raw for accuracy, or use cooked weight entries specifically.
Hitting calories but ignoring protein — a 1,800 calorie day with 60g protein is very different from 1,800 calories with 180g protein in terms of muscle retention.
Over-precision — you don't need to hit targets to the gram. Within 5–10g is fine. Consistency over weeks matters more than perfection on any single day.