Macronutrient Calculator -- Protein, Carbs & Fat

Calculate your ideal daily macros based on your body, goals, and activity level

Calculate Your Daily Macros

Enter your details below to get personalized daily targets for protein, carbohydrates, and fat. Results update automatically as you adjust inputs.

pounds (lbs)
kilograms (kg)
feet
inches
centimeters (cm)
Balanced
30 / 40 / 30
P / C / F
Low Carb
40 / 25 / 35
P / C / F
High Protein
40 / 35 / 25
P / C / F
Keto
25 / 5 / 70
P / C / F
Your BMR
--
calories at rest
Your TDEE
--
maintenance calories
Daily Target
--
adjusted for goal
Protein
--g
-- cal
--%
Carbohydrates
--g
-- cal
--%
Fat
--g
-- cal
--%
Calorie Breakdown by Macronutrient
30%
40%
30%
Protein
Carbs
Fat
Per-Meal Breakdown
Meal Calories Protein Carbs Fat

How This Calculator Works

This macronutrient calculator uses a three-step process to determine your daily macro targets:

Step 1: Basal Metabolic Rate (BMR)

Your BMR is estimated using the Mifflin-St Jeor equation, which is widely regarded as the most accurate BMR formula for most adults:

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

Step 2: Total Daily Energy Expenditure (TDEE)

Your BMR is multiplied by an activity factor to account for daily movement and exercise:

Activity LevelFactorDescription
Sedentary1.2Little or no exercise, desk job
Lightly Active1.375Light exercise 1-3 days/week
Moderately Active1.55Moderate exercise 3-5 days/week
Very Active1.725Hard exercise 6-7 days/week
Extra Active1.9Athlete, physical job + daily training

Step 3: Macro Split

Your target calories (TDEE adjusted for goal) are divided among protein, carbs, and fat using your chosen ratio. Macronutrient calories per gram:

  • Protein: 4 calories per gram
  • Carbohydrates: 4 calories per gram
  • Fat: 9 calories per gram

Understanding the Diet Splits

Balanced (30/40/30)

The most common starting point. Moderate protein supports muscle maintenance, carbs fuel daily activity, and adequate fat supports hormone production. Recommended for general health and fitness.

Low Carb (40/25/35)

Reduces carbohydrate intake while increasing protein and fat. Can help with blood sugar management and may improve satiety. Good for people who feel better on fewer carbs but find keto too restrictive.

High Protein (40/35/25)

Maximizes protein intake to support muscle building and recovery. Ideal for strength athletes, bodybuilders, or anyone in a caloric deficit who wants to preserve lean mass. Higher protein also increases the thermic effect of food.

Keto (25/5/70)

Very low carbohydrate, high fat diet designed to induce ketosis. Typically limits carbs to 20-50g per day. Requires careful planning and may not be sustainable long-term for everyone. Consult a healthcare provider before starting.

Examples

Example 1 -- Maintenance, Balanced Diet

Input: 30-year-old male, 180 lbs (82 kg), 5'10" (178 cm), moderately active

  • BMR = (10 x 82) + (6.25 x 178) - (5 x 30) + 5 = 820 + 1112.5 - 150 + 5 = 1,788 cal
  • TDEE = 1,788 x 1.55 = 2,771 cal
  • Balanced split (30/40/30): Protein 208g, Carbs 277g, Fat 92g

Example 2 -- Fat Loss, High Protein

Input: 28-year-old female, 140 lbs (64 kg), 5'5" (165 cm), lightly active, lose 1 lb/week

  • BMR = (10 x 64) + (6.25 x 165) - (5 x 28) - 161 = 640 + 1031 - 140 - 161 = 1,370 cal
  • TDEE = 1,370 x 1.375 = 1,884 cal
  • Target = 1,884 - 500 = 1,384 cal
  • High protein split (40/35/25): Protein 138g, Carbs 121g, Fat 38g

Example 3 -- Bulking, Balanced Diet

Input: 25-year-old male, 160 lbs (73 kg), 5'9" (175 cm), very active, bulk +500 cal

  • BMR = (10 x 73) + (6.25 x 175) - (5 x 25) + 5 = 730 + 1094 - 125 + 5 = 1,704 cal
  • TDEE = 1,704 x 1.725 = 2,939 cal
  • Target = 2,939 + 500 = 3,439 cal
  • Balanced split (30/40/30): Protein 258g, Carbs 344g, Fat 115g

Macronutrient Reference Guide

Each macronutrient plays a distinct role in your body. Here is what they do and where to find them:

MacronutrientCalories/gFunctionsGood Sources
Protein 4 Muscle repair, immune function, enzyme and hormone production, satiety Chicken, fish, eggs, Greek yogurt, tofu, lentils, whey protein
Carbohydrates 4 Primary energy source, brain fuel, glycogen replenishment, fiber intake Rice, oats, potatoes, fruits, vegetables, whole grain bread, beans
Fat 9 Hormone production, vitamin absorption (A, D, E, K), cell membranes, insulation Olive oil, avocado, nuts, seeds, fatty fish, cheese, dark chocolate

Frequently Asked Questions

What are macronutrients?

Macronutrients are the three main nutrients your body needs in large amounts: protein (4 calories per gram), carbohydrates (4 calories per gram), and fat (9 calories per gram). Together they make up the total calories in your diet. Each plays a distinct role -- protein builds and repairs tissue, carbs provide energy, and fat supports hormones and nutrient absorption.

How do I calculate my macros?

First, calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation. Multiply by an activity factor to get your Total Daily Energy Expenditure (TDEE). Adjust for your goal (subtract calories for fat loss, add for muscle gain). Then split the resulting calories among protein, carbs, and fat based on your chosen ratio.

What is the best macro split for weight loss?

A higher protein approach (35-40% protein) is generally recommended for weight loss because it preserves muscle mass during a caloric deficit and increases satiety. A common effective split is 40% protein, 35% carbs, 25% fat. However, the best split is one you can consistently follow. Adherence matters more than the exact ratio.

How much protein do I need per day?

General guidelines suggest 0.7-1.0 grams per pound of body weight for active individuals aiming to build or preserve muscle. The minimum RDA for sedentary adults is 0.36 grams per pound (0.8 g/kg). Athletes and those in a caloric deficit may benefit from even higher intakes of 1.0-1.2 grams per pound.

What is the difference between macros and calories?

Calories measure total energy in food. Macros are the specific nutrients (protein, carbs, fat) that provide those calories. Tracking macros gives you more control over body composition than tracking calories alone, because the source of your calories affects muscle retention, energy, and how full you feel.

What is IIFYM (If It Fits Your Macros)?

IIFYM is a flexible dieting approach where you can eat any food as long as it fits within your daily macro targets. Unlike strict meal plans, IIFYM allows food variety and flexibility, which can improve long-term adherence. The approach still emphasizes hitting your protein, carb, and fat targets for the day.

How accurate is this calculator?

This calculator uses the Mifflin-St Jeor equation, which research shows is the most accurate BMR formula for most adults (typically within 10% of measured values). However, individual metabolism varies based on genetics, body composition, hormones, and other factors. Use the results as a starting point and adjust based on your actual progress over 2-4 weeks.

Does this calculator store my data?

No. All calculations run entirely in your browser. No data is sent to any server, and nothing is stored.

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Privacy & Limitations

Privacy: This calculator runs entirely in your browser. No personal data -- including your weight, height, age, or macro results -- is transmitted or stored anywhere.

Limitations: The Mifflin-St Jeor equation provides an estimate of caloric needs. Individual metabolism varies based on genetics, body composition, hormonal status, and other factors. These results are a starting point, not a prescription. Adjust based on real-world progress and consult a registered dietitian or healthcare provider for personalized nutrition advice.

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Macronutrient Calculator FAQ

What are macronutrients?

Macronutrients are the three main nutrients your body needs in large amounts: protein (4 calories per gram), carbohydrates (4 calories per gram), and fat (9 calories per gram). Together they make up the total calories in your diet and each plays a distinct role in energy, muscle repair, hormone production, and organ function.

How do I calculate my macros?

First, calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation. Multiply by an activity factor to get your Total Daily Energy Expenditure (TDEE). Adjust for your goal (deficit for fat loss, surplus for muscle gain). Then split the resulting calories among protein, carbs, and fat based on your chosen diet approach.

What is the best macro split for weight loss?

A common effective split for weight loss is 40% protein, 35% carbs, and 25% fat. Higher protein helps preserve muscle mass during a caloric deficit. However, the best split depends on your preferences, activity level, and how well you adhere to the plan. Consistency matters more than the exact ratio.

How much protein do I need per day?

General guidelines suggest 0.7-1.0 grams of protein per pound of body weight for active individuals. For sedentary adults, 0.36 grams per pound (0.8 g/kg) is the minimum RDA. Athletes and those building muscle may benefit from 1.0-1.2 grams per pound.

What is the difference between macros and calories?

Calories measure total energy in food. Macros (protein, carbs, fat) are the specific nutrients that provide those calories. Tracking macros gives you more control over body composition than tracking calories alone, because the source of your calories affects muscle retention, energy levels, and satiety.

What macro split is best for building muscle?

For muscle building, a common split is 35% protein, 40% carbs, and 25% fat with a caloric surplus of 250-500 calories above TDEE. Adequate protein supports muscle protein synthesis, while carbohydrates fuel intense training sessions and replenish glycogen stores.

How accurate is this macronutrient calculator?

This calculator uses the Mifflin-St Jeor equation, which research has shown to be the most accurate BMR formula for most adults (within about 10% of measured values). However, individual metabolism varies. Use the results as a starting point and adjust based on your actual progress over 2-4 weeks.

Does this calculator store my data?

No. All calculations run entirely in your browser. No data is sent to any server, and nothing is stored.

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