Macro Calculator

Get your personalised protein, carbohydrate, and fat targets based on your body stats and fitness goal.

Unit System

Age

yrs

Gender

Height

ft in

Weight

Activity Level

Goal

Weekly Change Goal

Carb / Fat Preference

BMR Formula

Body Fat %

Your Daily Targets

TDEE

Target Calories

Protein

Carbs

Fat

Protein Carbs Fat

📖 What is a Macro Calculator?

A macro calculator determines your daily targets for the three macronutrients - protein, carbohydrates, and fat - based on your body stats, activity level, and fitness goal. Unlike a simple calorie counter, this calculator first estimates your Total Daily Energy Expenditure (TDEE) using a validated BMR formula, then adjusts that number up or down based on your goal (deficit for weight loss, surplus for muscle gain), and finally splits the resulting calorie target into optimal macro grams.

Macronutrients serve distinct roles in the body. Protein builds and repairs muscle tissue, supports immune function, and is the most satiating macronutrient - it keeps you full longer than equivalent calories from carbs or fat. Carbohydrates are the body's preferred energy source for high-intensity exercise and fuel the brain. Fats are essential for hormone production, fat-soluble vitamin absorption (A, D, E, K), and cell membrane integrity.

Different fitness goals require different macro splits. For weight loss, a higher protein percentage preserves muscle mass during a calorie deficit. For muscle gain, higher carbohydrates support training intensity and post-workout glycogen replenishment. Ketogenic approaches dramatically reduce carbohydrates to shift the body's fuel source to fat (ketosis). The carb/fat preference slider lets you further fine-tune the split to match your dietary style - low carb/high fat, balanced, or high carb/low fat.

The flexible dieting philosophy (IIFYM - If It Fits Your Macros) uses these targets as a framework without restricting specific foods, making it one of the most sustainable dietary approaches for long-term results. Research consistently shows that adherence to any diet is the #1 predictor of success - macros give you a flexible target to hit rather than a rigid meal plan to follow.

📐 Formula

Step 1 - BMR (Mifflin-St Jeor):

Men: BMR = 10 × W(kg) + 6.25 × H(cm) − 5 × Age + 5

Women: BMR = 10 × W(kg) + 6.25 × H(cm) − 5 × Age − 161

BMR (Katch-McArdle): BMR = 370 + 21.6 × LBM(kg) where LBM = W × (1 − BF%)

Step 2 - TDEE: TDEE = BMR × Activity Factor

Activity factors: Sedentary 1.2 | Light 1.375 | Moderate 1.55 | Very active 1.725 | Extra active 1.9

Step 3 - Target calories: Target = TDEE ± weekly rate adjustment (e.g. −500 kcal/day = −0.5 kg/week)

Step 4 - Macros:

Protein (g) = Target × protein% ÷ 4 (1 g protein = 4 kcal)

Carbs (g) = Target × carb% ÷ 4 (1 g carbs = 4 kcal)

Fat (g) = Target × fat% ÷ 9 (1 g fat = 9 kcal)

📖 How to Use This Calculator

Select your unit system (Metric or Imperial), then enter your age and gender.

Enter your height and weight - imperial users enter feet/inches and pounds.

Select your activity level - be honest; overestimating is the most common mistake.

Choose your goal and the weekly change rate - 0.5 kg/week is aggressive; 0.25 kg/week is safer and easier to sustain.

Set your carb/fat preference and choose a BMR formula (Katch-McArdle requires body fat %).

Click Calculate Macros - your TDEE, target calories, and daily macro grams are shown with a visual split bar.

💡 Example Calculations

Example 1 - Weight loss: 30-year-old male, 80 kg, 175 cm, moderately active

BMR (Mifflin) = 10×80 + 6.25×175 − 5×30 + 5 = 800 + 1093.75 − 150 + 5 = 1,748 kcal

TDEE = 1,748 × 1.55 = 2,710 kcal

Target (−500 deficit) = 2,710 − 500 = 2,210 kcal

Balanced split - Protein 35%: 2,210×0.35÷4 = 193 g | Carbs 35%: 193 g | Fat 30%: 2,210×0.30÷9 = 74 g

Try this example →

Example 2 - Muscle gain: 25-year-old female, 60 kg, 163 cm, very active, Katch-McArdle (22% BF)

LBM = 60 × (1 − 0.22) = 46.8 kg | BMR (Katch) = 370 + 21.6 × 46.8 = 1,381 kcal

TDEE = 1,381 × 1.725 = 2,382 kcal

Target (+250 surplus) = 2,382 + 250 = 2,632 kcal

High-carb split - Protein 30%: 2,632×0.30÷4 = 197 g | Carbs 50%: 329 g | Fat 20%: 2,632×0.20÷9 = 58 g

Try this example →

Frequently Asked Questions

What are macros?+

Macronutrients (macros) are the three main nutrient categories that provide energy: protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g). Unlike micronutrients (vitamins, minerals), macros are needed in large amounts. Tracking macros ensures you're getting the right fuel mix for your goal, not just the right calories.

How much protein do I need per day?+

For most people seeking to maintain or build muscle: 1.6–2.2 g per kg of body weight. Beginners may gain muscle at 1.6 g/kg; advanced lifters and those in a calorie deficit benefit from the higher end (2.0–2.4 g/kg). For sedentary individuals, the RDA is 0.8 g/kg, but this is a minimum, not optimal for body composition.

What is IIFYM?+

IIFYM stands for 'If It Fits Your Macros' - a flexible dieting approach where you track macronutrient targets rather than following a rigid meal plan. As long as your daily protein, carb, and fat totals are hit, the specific foods can be flexible. This improves adherence compared to restrictive diets while still achieving body composition goals.

Should I eat more carbs or fat?+

Both work for weight loss and muscle gain if protein and total calories are controlled. Carbs are preferred by most athletes as they fuel high-intensity exercise through glycolysis. Fat is used more by endurance athletes and those eating low-carb diets. Personal preference and how you feel on each approach matter most for long-term adherence.

How do I hit my macros every day?+

Use a food tracking app (MyFitnessPal, Cronometer) to log meals. Start with protein-first planning: build meals around your protein source, then add carbs and fats to fit. Batch cooking and meal prepping makes it far easier to hit targets consistently.

What is the Mifflin-St Jeor formula?+

Mifflin-St Jeor is the most accurate BMR formula for most people. For men: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age + 5. For women: BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 161. It is then multiplied by an activity factor to get TDEE (total daily energy expenditure).

What is the Katch-McArdle formula?+

The Katch-McArdle formula uses lean body mass (LBM) instead of total weight: BMR = 370 + 21.6 × LBM(kg). It is more accurate for lean or athletic individuals where body fat percentage is known. You need to enter your body fat % to use it.

How much protein do I need per day to build muscle?+

Current research shows that 1.6-2.2 g of protein per kg of body weight per day is the effective range for maximising muscle protein synthesis during resistance training. Beyond 2.2 g per kg, additional protein shows diminishing returns for most people. For a 70 kg person, that is 112-154 g of protein per day. Higher intakes up to 3.1 g per kg may be beneficial during aggressive calorie restriction to preserve muscle mass.

What is the best macro ratio for weight loss?+

No single macro ratio is universally best for weight loss - total calorie intake is the primary driver. That said, higher protein (30-40% of calories) is associated with better fat loss outcomes because protein is the most satiating macronutrient and has the highest thermic effect (25-30% of protein calories are burned during digestion). Low-carb and low-fat diets produce similar weight loss when protein and calories are matched.