Macro Nutrients Calculator
Calculate your daily protein, carbs, and fat targets from your BMR and TDEE. Supports Balanced, Low Carb, High Protein, and Ketogenic plans with meal distribution.
What Are Macronutrients?
Macronutrients — commonly called "macros" — are the three main classes of nutrients that provide calories and form the structural basis of your diet:
Protein
4 kcal/g
The building block of muscle, enzymes, and hormones. Essential for muscle repair, immune function, and satiety. Found in meat, fish, eggs, dairy, legumes, and soy.
Carbohydrates
4 kcal/g
The body's primary and preferred energy source. Found in grains, fruit, vegetables, legumes, and dairy. Fuels the brain and working muscles during exercise.
Fat
9 kcal/g
Essential for hormone production, fat-soluble vitamin absorption (A, D, E, K), and cell membrane integrity. Found in oils, nuts, seeds, avocado, dairy, and fatty fish.
How to Calculate Your Macros
- 1
Calculate BMR (Basal Metabolic Rate)
BMR is the number of calories your body burns at complete rest to maintain basic functions. This calculator uses the Mifflin-St Jeor equation — the most accurate formula for most adults.
Male: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age + 5 Female: BMR = 10×weight(kg) + 6.25×height(cm) − 5×age − 161 - 2
Multiply by Activity Multiplier (TDEE)
Multiply BMR by your activity level to get Total Daily Energy Expenditure — the actual number of calories you burn each day.
TDEE = BMR × Activity Multiplier (1.2 – 1.9) - 3
Apply Goal Adjustment
Adjust TDEE based on your goal: eat less to lose fat, eat more to gain muscle, or eat at maintenance to stay the same.
Lose: ×0.80 | Maintain: ×1.00 | Gain: ×1.10 - 4
Distribute into Macros
Apply your chosen macro split percentage to the target calorie total. Divide by calories-per-gram for each macro.
Protein/Carbs = kcal ÷ 4 | Fat = kcal ÷ 9
Macro Ratios by Goal
| Plan | Protein | Carbs | Fat | Best For |
|---|---|---|---|---|
| Balanced | 30% | 40% | 30% | General health, maintenance, beginners |
| Low Carb | 40% | 30% | 30% | Fat loss, blood sugar management |
| High Protein | 35% | 40% | 25% | Muscle gain, body recomposition |
| Ketogenic | 30% | 10% | 60% | Fat adaptation, therapeutic, extreme fat loss |
How Many Grams of Protein Should I Eat?
Protein requirements depend on your goals, body weight, and activity level. General guidelines:
Minimum recommended daily intake (RDA)
Supports muscle maintenance and recovery
Optimises muscle protein synthesis
Higher protein helps maintain lean mass in a deficit
For elite athletes or very high training volumes
This calculator uses a percentage-of-calorie approach rather than a per-kg protein target. For precise body-composition goals, consider cross-referencing with a 1.6–2.2 g/kg protein target.
Example Macro Calculations
Male, 30, 175 cm, 75 kg, Moderate activity, Lose Weight, Balanced
Female, 28, 165 cm, 60 kg, Light activity, Maintain, High Protein
Male, 25, 180 cm, 80 kg, Very Active, Gain Muscle, Balanced
Female, 35, 160 cm, 65 kg, Sedentary, Lose Weight, Low Carb
Frequently Asked Questions
What are macros, and why do they matter?
Macros are protein, carbohydrates, and fat — the three nutrients that provide all of your dietary calories. Tracking macros gives you more granular control over body composition than simply counting calories, because the ratio of protein to carbs to fat affects muscle retention, fat loss, energy levels, and hormonal health.
How many macros should I eat to lose weight?
For fat loss, aim for a calorie deficit of 15–25% below your TDEE. A higher protein intake (35–40% of calories) helps preserve muscle mass while in a deficit. A low-carb split (40% protein / 30% carbs / 30% fat) works well for many people, though any calorie-controlled diet can produce fat loss.
Is high protein better for fat loss?
Yes, research consistently shows that higher protein diets are superior for fat loss because protein is more satiating, has a higher thermic effect (burns more calories during digestion), and preserves lean muscle mass — which keeps metabolism higher during a caloric deficit.
What macro ratio is best for muscle gain?
For muscle gain, prioritise protein (1.6–2.2 g per kg of bodyweight) and eat in a moderate calorie surplus (10–15% above TDEE). A high-protein split (35% protein / 40% carbs / 25% fat) supports both muscle building and sustained energy for training. Carbohydrates are important for fuelling workouts and supporting recovery.
Can macros help with weight loss even if calories are the same?
Yes, to a degree. Protein has a thermic effect of 20–30% compared to 5–10% for carbs and 0–3% for fat, meaning you burn more calories simply by digesting protein. Additionally, higher protein and fat intake tends to improve satiety, reducing the likelihood of overeating.
How accurate is the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation is the most validated formula for estimating BMR in the general population and is recommended by the Academy of Nutrition and Dietetics. However, all equations are estimates. Individual metabolic variation means your actual needs may differ by 10–20%. Adjust your intake based on real-world results over 2–4 weeks.