Macro Calculator
Calculate your optimal daily macronutrient intake — protein, carbohydrates, and fat — based on your goals.
What Is a Macro Calculator?
Macronutrients — protein, carbohydrates, and fat — are the three categories of nutrients that provide your body with energy. While total calorie intake determines whether you gain, lose, or maintain weight, the ratio of macronutrients influences your body composition, energy levels, workout performance, and overall health. Understanding and tracking your macros gives you far more control over your nutrition than calorie counting alone.
Protein is essential for building and repairing muscle tissue, producing enzymes and hormones, and supporting immune function. Carbohydrates are your body's preferred energy source, fuelling everything from brain function to intense exercise. Dietary fat is critical for hormone production, nutrient absorption (vitamins A, D, E, and K are fat-soluble), and cell membrane integrity. The International Society of Sports Nutrition and other bodies provide evidence-based guidelines for optimal macro ratios depending on individual goals.
This macro calculator first estimates your Total Daily Energy Expenditure (TDEE) using the Mifflin-St Jeor equation for Basal Metabolic Rate (BMR), then applies an activity multiplier. Based on your selected goal — fat loss, maintenance, or muscle gain — it adjusts your total calories and distributes them across protein, carbohydrates, and fat using evidence-based ratios. The result is a personalised daily macronutrient target in grams that you can use to plan meals and track your nutrition.
How Do You Use This Macro Calculator?
Enter your age, gender, height, weight, activity level, and fitness goal (lose fat, maintain, or build muscle) to calculate your recommended daily macronutrient split.
- Enter your age, gender, height, and current body weight.
- Select your activity level from sedentary to very active.
- Choose your primary goal: lose fat, maintain weight, or build muscle.
- Review your estimated TDEE and adjusted calorie target.
- Check your recommended daily intake for protein, carbohydrates, and fat in grams.
- Use the gram targets to plan meals or enter into a food tracking app.
How Does the Macro Calculator Formula Work?
The formula used: TDEE = BMR * Activity Factor; Protein (g) = target g/kg * body weight; Fat (g) = (TDEE * fat%) / 9; Carbs (g) = (TDEE - protein cal - fat cal) / 4
The calculator first estimates your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, which research has shown to be the most accurate predictive equation for most people.
Men: BMR = (10 * weight in kg) + (6.25 * height in cm) - (5 * age) + 5
Women: BMR = (10 * weight in kg) + (6.25 * height in cm) - (5 * age) - 161
Your BMR is then multiplied by an activity factor (1.2 for sedentary up to 1.9 for very active) to get your TDEE. Calories are adjusted for your goal (typically -500 kcal for fat loss, +250-500 for muscle gain), then distributed: protein at 1.6-2.2 g/kg body weight, fat at 20-30% of total calories, and remaining calories allocated to carbohydrates.
What Are Some Example Calculations?
An 80 kg male with a TDEE of 2,500 kcal aiming to build muscle: Protein = 2.0 g/kg * 80 = 160 g (640 kcal), Fat = 25% of 2,750 = 76 g (688 kcal), Carbs = (2,750 - 640 - 688) / 4 = 356 g.
A 75 kg, 30-year-old male, 175 cm tall, moderately active, aiming to lose fat.
BMR = (10 * 75) + (6.25 * 175) - (5 * 30) + 5 = 750 + 1094 - 150 + 5 = 1,699 kcal. TDEE = 1,699 * 1.55 = 2,633 kcal. Fat loss target = 2,633 - 500 = 2,133 kcal. Protein = 2.0 g/kg * 75 = 150 g (600 kcal). Fat = 25% of 2,133 = 59 g (533 kcal). Carbs = (2,133 - 600 - 533) / 4 = 250 g.
Daily targets: 2,133 kcal — 150 g protein, 250 g carbs, 59 g fat.
A 60 kg, 25-year-old female, 163 cm tall, lightly active, aiming to maintain weight.
BMR = (10 * 60) + (6.25 * 163) - (5 * 25) - 161 = 600 + 1019 - 125 - 161 = 1,333 kcal. TDEE = 1,333 * 1.375 = 1,833 kcal. Protein = 1.6 g/kg * 60 = 96 g (384 kcal). Fat = 27% of 1,833 = 55 g (495 kcal). Carbs = (1,833 - 384 - 495) / 4 = 239 g.
Daily targets: 1,833 kcal — 96 g protein, 239 g carbs, 55 g fat.
A 90 kg, 28-year-old male, 183 cm tall, very active, aiming to build muscle.
BMR = (10 * 90) + (6.25 * 183) - (5 * 28) + 5 = 900 + 1144 - 140 + 5 = 1,909 kcal. TDEE = 1,909 * 1.725 = 3,293 kcal. Surplus target = 3,293 + 350 = 3,643 kcal. Protein = 2.2 g/kg * 90 = 198 g (792 kcal). Fat = 25% of 3,643 = 101 g (911 kcal). Carbs = (3,643 - 792 - 911) / 4 = 485 g.
Daily targets: 3,643 kcal — 198 g protein, 485 g carbs, 101 g fat.
When Should You Use a Macro Calculator?
Use the macro calculator when you have a specific body composition goal such as losing fat while preserving muscle, building lean mass, or optimising athletic performance. Counting macros provides more precision than simply tracking calories, because it ensures you get enough protein for muscle maintenance, sufficient fat for hormonal health, and adequate carbohydrates for energy and performance.
This calculator is especially useful when starting a new diet or training programme, when progress has stalled and you need to adjust your intake, or when transitioning between phases (e.g., moving from a fat-loss phase to maintenance or a lean bulk). Coaches, dietitians, and athletes regularly use macro-based nutrition planning as the foundation of their dietary strategies.
What Do These Terms Mean?
What Are the Best Tips to Know?
- Weigh food with a kitchen scale rather than estimating portions — studies show people underestimate intake by 30-50%.
- Hit your protein target first each day, as it is the most important macro for body composition.
- Adjust macros every 4-6 weeks based on progress rather than changing them weekly.
- Allow a margin of plus or minus 5-10 grams on each macro — perfection is not required for results.
- Distribute protein intake across 3-5 meals per day for optimal muscle protein synthesis.
What Mistakes Should You Avoid?
- Setting protein too low during a calorie deficit, which accelerates muscle loss and slows metabolism.
- Cutting fat below 20% of total calories, which can impair hormone production and nutrient absorption.
- Ignoring fibre intake within the carbohydrate target — aim for at least 25-30 g of fibre daily.
- Recalculating macros daily based on minor weight fluctuations instead of using a stable weekly average.
Frequently Asked Questions
What is the best macro ratio for fat loss?
A common evidence-based approach for fat loss is 30% protein, 40% carbs, and 30% fat, but the most important factor is maintaining high protein (1.6-2.2 g/kg body weight) while in a calorie deficit. The carb-to-fat ratio is less critical and can be adjusted based on personal preference.
Do I need to hit my macros exactly every day?
No. Aiming within 5-10 grams of each target is sufficient. Consistency over the week matters more than perfection on any single day. Focus on hitting your protein target as the priority.
How much protein do I really need?
Research supports 1.6-2.2 g per kilogram of body weight per day for people who exercise regularly. Sedentary individuals need less (0.8-1.0 g/kg), while those in a calorie deficit benefit from the higher end of the range to preserve muscle.
Should I eat the same macros on rest days?
For most people, keeping macros consistent every day produces the best results. Some advanced athletes use carb cycling (higher carbs on training days, lower on rest days), but this adds complexity without significant benefit for most people.
Why are my macro targets different from my friend's?
Macro targets depend on your individual body weight, height, age, gender, activity level, and goals. Two people with different body compositions or activity levels will have very different calorie and macro needs even if their goals are the same.
Can I swap carbs and fat grams freely?
Not gram-for-gram, because carbs provide 4 calories per gram while fat provides 9 calories per gram. If you reduce carbs, you can add roughly half as many grams of fat to keep calories the same, and vice versa.
How do I track my macros?
Use a food tracking app such as MyFitnessPal, Cronometer, or MacroFactor. Weigh your food with a kitchen scale for accuracy, especially when starting out. Most people develop the ability to estimate portions after a few weeks of consistent tracking.
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