Macro Calculator

Calculate your TDEE and daily macronutrient targets using the Mifflin-St Jeor equation. Results update instantly.

Your Stats

yrs
lb
ft
in
Basal Metabolic Rate (BMR)
—
calories at complete rest
Total Daily Energy (TDEE)
—
calories with activity
Target Calories
—
adjusted for your goal

Macro Split

Carbohydrates 40%
Protein 30%
Fat 30%
Macro percentages must add up to 100%.
Carbohydrates
—
— cal
Protein
—
— cal
Fat
—
— cal

How to Use the Macro Calculator

This macro calculator uses the Mifflin-St Jeor equation — the gold standard for estimating calorie needs — to calculate your Total Daily Energy Expenditure (TDEE), then breaks that into protein, carbohydrate, and fat grams based on your selected macro split. All results update live as you adjust any input.

Step 1: Enter Your Body Stats

Input your age, sex, weight, and height. You can toggle between pounds/kilograms and feet-inches/centimeters. The calculator converts units internally, so use whichever system you are comfortable with. Accurate inputs produce accurate results — weigh yourself in the morning after using the bathroom for the most consistent reading.

Step 2: Select Your Activity Level

The activity multiplier is the biggest source of variation in TDEE estimates. Be honest about your typical week rather than your best week. Sedentary (1.2x) applies if you sit most of the day and do not exercise. Lightly active (1.375x) applies for 1-3 days per week of light movement. Moderately active (1.55x) fits most people who exercise consistently 3-5 days per week. Active (1.725x) suits athletes or those with physically demanding jobs combined with regular training. Very active (1.9x) is reserved for professional athletes or people with extremely demanding physical jobs plus daily intense training.

Step 3: Choose Your Goal

Your goal adjusts calories above or below your TDEE. Weight loss subtracts 500 calories per day, which creates a weekly deficit of 3,500 calories — roughly equivalent to one pound of fat loss per week. Maintenance keeps you at TDEE. Lean bulk adds 250 calories for slow, controlled muscle building that minimizes fat gain. Standard bulk adds 500 calories for faster muscle accumulation. If none of these fit your situation, use the custom adjustment field to enter any calorie offset.

Step 4: Pick a Macro Split

Once your target calories are set, the macro split determines how those calories are divided among carbohydrates, protein, and fat. Each preset is designed for a specific dietary approach:

  • Balanced (40/30/30): 40% carbs, 30% protein, 30% fat. A versatile split that works for general fitness, endurance training, and everyday health. This is a solid starting point for most people.
  • Low-Carb (25/35/40): 25% carbs, 35% protein, 40% fat. Reduces carbohydrate intake while keeping protein high. Popular for fat loss phases and metabolic health improvement.
  • Keto (5/25/70): 5% carbs, 25% protein, 70% fat. Designed to put the body into nutritional ketosis, where fat becomes the primary fuel source. Requires strict adherence to keep carbs under approximately 20-50 grams per day.
  • High-Protein (40/40/20): 40% protein, 40% carbs, 20% fat. Maximizes muscle protein synthesis. Ideal for body recomposition — building muscle while losing fat — and for preserving muscle during a calorie deficit.
  • Custom: Drag the sliders to any combination that adds to 100%. Useful when you follow a specific diet plan or have preferences outside the standard presets.

Understanding Your Results

The calculator outputs three calorie figures and three macro breakdowns. BMR is your Basal Metabolic Rate — the calories your body burns at complete rest to sustain basic functions like breathing and circulation. TDEE is BMR multiplied by your activity factor. Target Calories is TDEE adjusted by your goal offset. The macro cards show grams per day for each macronutrient alongside the calories they contribute. Carbohydrates and protein each provide 4 calories per gram, while fat provides 9 calories per gram.

Mifflin-St Jeor Equation

The Mifflin-St Jeor equation was published in 1990 and has been validated in numerous studies as the most accurate formula for predicting resting energy expenditure in the general population. It requires age, sex, weight in kilograms, and height in centimeters:

Men: BMR = (10 x weight) + (6.25 x height) - (5 x age) + 5

Women: BMR = (10 x weight) + (6.25 x height) - (5 x age) - 161

Where weight is in kilograms and height is in centimeters. The only difference between the male and female formulas is the constant at the end (+5 vs -161), which reflects the average difference in lean body mass between sexes.

How to Adjust Based on Real Results

No equation perfectly predicts individual metabolism. Track your weight daily and calculate a 7-day rolling average. If your weight trend does not match your expected goal after 2-4 weeks, adjust your target calories by 100-150 calories in the appropriate direction. Expect some water weight fluctuation of 1-3 pounds day to day — focus on the weekly trend, not daily readings. Consistency in logging and measurement gives you the data needed to calibrate accurately.

Protein Targets and Muscle Retention

Protein is the most important macronutrient for body composition. A high protein intake preserves lean muscle mass during a calorie deficit, accelerates recovery from training, and has the highest thermic effect of food (roughly 25-30% of protein calories are used in digestion). For active individuals, aim for at least 0.7 grams of protein per pound of body weight. During aggressive cuts or very high training volumes, 1.0 gram per pound provides an added buffer against muscle loss. The high-protein preset in this calculator typically lands near these targets for most people.

FAQ

TDEE stands for Total Daily Energy Expenditure — the total number of calories your body burns each day including activity. It is calculated by first finding your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, then multiplying by an activity factor ranging from 1.2 (sedentary) to 1.9 (very active). The Mifflin-St Jeor equation for men is: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5. For women: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age - 161.
Most research supports 0.7 to 1.0 grams of protein per pound of body weight (1.6 to 2.2 g per kg) for people who exercise regularly. For muscle building, the upper end (1.0 g/lb) is recommended. For sedentary individuals, 0.36 g/lb (0.8 g/kg) meets basic needs. The macro calculator uses your selected protein percentage of target calories to calculate grams, since 1 gram of protein provides 4 calories.
A cut (weight loss) means eating below your TDEE — typically 500 calories below — to create a deficit that burns roughly 1 pound of fat per week. Maintenance means eating at TDEE to hold your current weight. A lean bulk adds 250 calories above TDEE for slow, lean muscle gain with minimal fat. A standard bulk adds 500 calories for faster muscle gain at the cost of more fat accumulation.
The best macro split depends on your goals and preferences. Balanced (40% carbs / 30% protein / 30% fat) works well for general fitness. High-protein (40% protein / 40% carbs / 20% fat) is ideal for muscle building and body recomposition. Low-carb (25% carbs / 35% protein / 40% fat) suits those who prefer fewer carbohydrates. Keto (5% carbs / 25% protein / 70% fat) is for strict ketogenic diets. Use the custom sliders to dial in any split that fits your lifestyle.
The Mifflin-St Jeor equation is considered the most accurate predictive equation for resting metabolic rate in most adults, with studies showing it estimates RMR within 10% for roughly 82% of people. It outperforms the older Harris-Benedict equation in most populations. However, it cannot account for body composition — muscular individuals may burn more than predicted, while those with higher body fat may burn less. Treat the result as a starting point and adjust based on real-world results over 2-4 weeks.

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