Online Macro Calculator - Calculate Your Daily Protein, Carbs & Fats

What Is This Tool?

The Macro Calculator estimates your daily macronutrient targets — protein, carbohydrates, and fat — for four different eating styles: balanced, low fat, low carb, and high protein. It first estimates your daily energy needs from your gender, age, height, weight, activity level, and goal, using one of three BMR formulas, then splits that energy into grams of each macronutrient, alongside sugar and saturated fat guidance and a total food energy figure. You can work in metric or imperial units and download the table as a PDF. All figures are general estimates, not personalized nutrition or medical advice.

How to Use This Tool?

• Select your gender and units, then enter your age, height, and weight.
• Choose your activity level and your weight goal.
• Optionally open Options to pick a BMR formula, adding body fat for Katch-McArdle.
• Click Calculate, then download the result as a PDF if needed.

Key Features

• Estimates protein, carb, and fat targets for balanced, low-fat, low-carb, and high-protein diets.
• Also shows sugar and saturated fat guidance plus total daily food energy.
• Offers three BMR formulas: Mifflin St Jeor, Revised Harris-Benedict, and Katch-McArdle.
• Adjusts totals for activity level and a maintain, loss, or gain goal.
• Works in metric or imperial units and exports the result as a PDF.

Examples

• A 30-year-old man at 182 cm and 80 kg, moderately active and maintaining weight, gets about 2,627 calories per day.
• For that person, the balanced diet works out to roughly 160 g protein, 350 g carbs, and 75 g fat.
• Switching to the low-carb style shifts the same energy toward more fat and less carbohydrate.
• Choosing a weight-loss goal lowers the daily calorie figure, which lowers the macro grams accordingly.

Common Use Cases

• Setting daily macro targets for a chosen eating style.
• Supporting fitness goals with protein, carb, and fat estimates.
• Comparing how balanced, low-fat, low-carb, and high-protein splits differ.
• Finding a daily food energy estimate to plan meals around.
• Adjusting targets when shifting between maintaining, losing, or gaining weight.

Tips & Best Practices

• Enter an accurate, recent weight and height for a better estimate.
• Pick the activity level that honestly reflects your typical week.
• Treat the macro grams as starting estimates and adjust based on real results.
• Choose a sustainable goal rather than the most aggressive one.
• Consult a registered dietitian or doctor before making big dietary changes.

Limitations

• All values are estimates and individual nutritional needs vary widely.
• It accepts ages from 15 to 80, so values outside that range are not supported.
• It does not account for medical conditions, pregnancy, or specific dietary requirements.
• It is for general information only and is not nutritional or medical advice.

Frequently Asked Questions

What are macros?

Macros, or macronutrients, are the three energy-providing nutrients in food: protein, carbohydrates, and fat.

How do the four diet styles differ?

They keep the same total food energy but divide it differently, shifting the balance of protein, carbs, and fat for each style.

Which BMR formula should I pick?

Mifflin St Jeor is a common general choice, Revised Harris-Benedict is an alternative, and Katch-McArdle is best if you know your body fat percentage.

Can I save my result?

Yes. Click Download Result as PDF to save the full macro table as a file.

Key Terminology

Macronutrients

The three nutrients that provide energy: protein, carbohydrates, and fat.

Basal Metabolic Rate (BMR)

The calories your body burns at rest to keep essential functions running.

Activity factor

A multiplier applied to BMR to account for how active you are during the day.

Protein

A macronutrient used to build and repair tissue, providing about four calories per gram.

Calorie deficit

Eating fewer calories than you burn, which the loss goals here are designed to estimate.

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