Macro Calculator: How to Find Your Perfect Protein, Carbs & Fat Targets

Counting macronutrients — protein, carbohydrates, and fat — is one of the most evidence-based approaches to body composition management. This calculator uses your personal stats, activity level, goal, and preferred diet style to produce a daily macro split and per-meal breakdown.

What Are Macronutrients?

Macronutrients are the three classes of nutrients that provide energy:

Macronutrient	Calories per gram	Primary role
Protein	4 kcal/g	Muscle repair, satiety, hormones
Carbohydrates	4 kcal/g	Primary energy fuel, brain function
Fat	9 kcal/g	Hormone production, fat-soluble vitamins

How We Calculate Your Macros

Step 1 — Calorie Target

We first calculate your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation (or Katch-McArdle if you provide body fat %) and an activity multiplier.

Your goal then adjusts the calorie target:

Goal	Adjustment	Typical use
Fat Loss (Cut)	TDEE × 0.80	Lose body fat while preserving muscle
Maintenance	TDEE × 1.00	Hold current body weight
Muscle Gain (Bulk)	TDEE × 1.10	Add muscle with minimal fat gain
Body Recomposition	TDEE × 1.00	Lose fat and gain muscle simultaneously

Step 2 — Macro Split

Calorie targets are divided by diet type and goal:

Diet Type	Protein	Carbs	Fat
Balanced (maintain)	30%	45%	25%
Low-Carb (maintain)	35%	25%	40%
High-Protein (maintain)	40%	40%	20%
Ketogenic (maintain)	25%	5%	70%

Ratios shift slightly depending on goal — cuts increase protein to protect muscle; bulks shift more calories to carbs for training fuel.

Step 3 — Convert to Grams

• Protein grams = protein calories ÷ 4
• Carbs grams = carbs calories ÷ 4
• Fat grams = fat calories ÷ 9

Choosing the Right Diet Type

Balanced

The most flexible and sustainable approach. Works well for most people and is compatible with all goals. Good starting point if you're new to tracking macros.

Low-Carb

Reduces insulin spikes and can improve fat oxidation. Popular for fat loss. Requires more planning around workouts (lower glycogen availability). Not ideal for high-volume training.

High-Protein

Prioritises protein above all else. Maximises muscle protein synthesis and satiety. Well-supported by research for both fat loss and muscle gain. Pairs well with strength training.

Ketogenic

Very high fat, minimal carbs (<50g/day). Can take 2–4 weeks to adapt (keto-adaptation). Best for individuals who have tried it before or have specific metabolic reasons. Not ideal for explosive or high-intensity sports.

The Importance of Protein

Protein is the most important macro to track because:

1. Muscle preservation: In a calorie deficit, inadequate protein causes muscle loss, lowering your BMR and worsening body composition over time.
2. Thermic effect: ~25–30% of protein calories are burned during digestion, effectively reducing net calorie absorption.
3. Satiety: Protein is the most satiating macronutrient, making it easier to stay in a calorie deficit.

Evidence-based protein targets:

• General fitness: 1.4–1.6 g/kg body weight
• Muscle gain: 1.6–2.2 g/kg
• Fat loss (preserve muscle): 2.0–2.4 g/kg

Body Recomposition

Body recomposition — simultaneously losing fat and gaining muscle — is possible but slower than focused cutting or bulking. It works best for:

• Beginners (who respond strongly to training regardless of diet)
• Individuals returning after a break
• Those with higher body fat percentages

The key is eating at maintenance, hitting high protein, and following a progressive resistance training programme.

Frequently Asked Questions

Should I hit my macros exactly every day? Aim for consistency over perfection. Hitting within ±5–10g on protein and ±10g on carbs/fat is excellent. Focus most on protein — carbs and fat can be traded off more flexibly (within limits for keto).

What if I don't have time to track everything? Use a protein-first approach: track only protein rigorously. This alone produces most of the benefit. Once comfortable, add carb and fat tracking.

Do I need to eat on a schedule? Meal timing matters less than total daily intake for most people. That said, distributing protein across 3–5 meals (20–40g per meal) maximises muscle protein synthesis throughout the day.

What is Katch-McArdle and when should I use it? Katch-McArdle calculates BMR from lean body mass instead of total weight, making it more accurate for people with known body fat percentages. Use it if you've measured your body fat (via DEXA, hydrostatic weighing, or our Body Fat Calculator).

How often should I recalculate my macros? Recalculate every 4–6 weeks, or whenever your weight changes by more than 3–4 kg, or when your activity level changes significantly.