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Macro Calculator: Protein, Carbs, Fat & Calories

Calculate daily calorie targets and optimal macronutrient grams (protein, carbohydrates, healthy fats) based on your fitness goals.

Quick Answer:Macros are the three primary energy nutrients: Protein (4 kcal/g), Carbohydrates (4 kcal/g), and Fat (9 kcal/g). Total calories = (Protein × 4) + (Carbs × 4) + (Fat × 9).

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How to Use the Macro Calculator (IIFYM Diet & Calories)

1Select your biological sex, age, height, and body weight.
2Select your daily physical activity level (from sedentary desk job to competitive athlete).
3Choose your primary goal: Weight Loss (-500 kcal deficit), Maintenance, or Muscle Gain (+400 kcal surplus).
4Select your preferred diet style (Balanced, Low Carb, High Carb, or Keto).
5Review your target daily calories, BMR, TDEE, and exact grams of protein, carbs, and fats.

Formula & How It Works

Mifflin-St Jeor & TDEE Formula

BMR_male = 10w + 6.25h - 5a + 5 | BMR_female = 10w + 6.25h - 5a - 161 | TDEE = BMR × Activity

Calculates Basal Metabolic Rate (BMR), scales by physical activity level to obtain Total Daily Energy Expenditure (TDEE), and divides goal calories into macro grams.

Worked Examples

28-Year-Old Male Weight Maintenance

Input: Male, 75kg, 178cm, 28 yrs, Moderate Activity, Balanced Diet

Explanation: BMR = 1,699 kcal. TDEE (1.55x) = 2,633 kcal. 30% Protein = 197g, 40% Carbs = 263g, 30% Fat = 88g.

Result: 2,633 kcal/day | Protein: 197g, Carbs: 263g, Fat: 88g

Female Fat Loss Deficit (-500 kcal)

Input: Female, 68kg, 165cm, 32 yrs, Light Activity, Low Carb Diet

Explanation: BMR = 1,411 kcal. TDEE (1.375x) = 1,940 kcal. Deficit target = 1,440 kcal/day.

Result: 1,440 kcal/day | Protein: 144g, Carbs: 72g, Fat: 64g

Male Lean Bulking Surplus (+400 kcal)

Input: Male, 80kg, 182cm, 24 yrs, Heavy Activity, High Carb

Explanation: Surplus fuels muscle protein synthesis during intense resistance training.

Result: 3,530 kcal/day | Protein: 221g, Carbs: 441g, Fat: 98g

Frequently Asked Questions

How many calories are in a gram of protein, carb, and fat?▼

Protein has 4 calories per gram, carbohydrates have 4 calories per gram, and dietary fat has 9 calories per gram.

How much protein should I eat per day?▼

Active individuals and those lifting weights typically benefit from 1.6 to 2.2 grams of protein per kilogram of body weight (0.7 to 1.0 grams per pound).

What is BMR versus TDEE?▼

BMR (Basal Metabolic Rate) is the baseline calories burned surviving at complete rest. TDEE (Total Daily Energy Expenditure) adds your daily movement, exercise, and digestion.

Why do fats have more calories than carbs?▼

Fat molecules have a higher density of carbon-hydrogen bonds, providing 9 calories per gram compared to 4 calories per gram for carbs and protein.

Is this calculation private?▼

Yes, all health calculations execute 100% locally in your web browser.

Quick Reference & Conversion Table

Diet Style	Carbohydrates %	Protein %	Healthy Fat %	Best Suited For
Balanced	40%	30%	30%	General health & sustainable weight management
Low Carb	20%	40%	40%	Fat loss, insulin sensitivity & satiety
High Carb Endurance	50%	25%	25%	Marathoners, cyclists & high-volume athletes
Ketogenic (Keto)	5%	25%	70%	Ketosis & therapeutic metabolic regimens

⚠️ Common Pitfalls to Avoid

•Overestimating activity level (e.g., classifying a 45-minute gym session as 'heavy activity' while sitting at a desk the other 23 hours).
•Dropping calories below clinical minimum safety thresholds (1,200 kcal for women, 1,500 kcal for men).
•Forgetting that alcohol contains 7 kcal per gram, which must be tracked when counting macros.

💡 Practical Real-World Uses

•Tracking nutrition in calorie counter apps like MyFitnessPal and MacroFactor.
•Bodybuilders and physique athletes prepping for cutting and bulking phases.
•Endurance runners optimizing carbohydrate fueling for half and full marathons.

Counting Macros vs Counting Calories

✓Counting calories controls overall body weight change (deficit for weight loss, surplus for weight gain).
✓Counting macros controls body composition (ensuring adequate protein prevents muscle loss while dieting).

Last reviewed & updated: 2026-11-01

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