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Macro Calculator

Calculate daily protein, carbohydrate, and fat targets based on your goals

Updated

What is the Macro Calculator?

Calculate your ideal daily protein, carbohydrate, and fat targets with this accurate macro calculator.

Built with the trusted Mifflin-St Jeor formula for BMR and activity-adjusted TDEE, it helps fitness enthusiasts, athletes, and anyone tracking nutrition hit their body composition goals — whether losing fat, building muscle, or maintaining weight.

Supports both metric and imperial units, multiple activity levels, customizable macro styles (Balanced, High Protein, Low Carb, Keto), optional body fat percentage for lean mass calculations, and goal-specific calorie adjustments.

How it works

This macro calculator combines proven physiological formulas with flexible nutrition presets to deliver personalized daily targets.

Step-by-step process:

  1. BMR Calculation — Uses the Mifflin-St Jeor equation, widely regarded as one of the most accurate for the general population:
  • Men: 10 × weight(kg) + 6.25 × height(cm) - 5 × age + 5
  • Women: 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 161

  1. TDEE Calculation — Multiplies BMR by an activity factor (1.2 Sedentary up to 1.9 Very Active).

  2. Goal Adjustment — Adds or subtracts calories based on your selected goal and desired weekly weight change (≈7700 kcal per kg of body weight).

  3. Macro Split — Applies your chosen style (Balanced, High Protein, Low Carb, or Keto) while respecting minimum protein and fat floors. You can override with custom g/kg values. When body fat % is provided, protein recommendations lean toward lean body mass.

Results show total daily calories plus exact gram targets for protein (4 kcal/g), carbohydrates (4 kcal/g), and fat (9 kcal/g), with percentage breakdowns and a visual calorie distribution bar.

All calculations run instantly in your browser with no data leaving your device.

Examples

30-year-old male, moderate activity, maintenance goal

Calculate macros for a 75kg, 175cm man who trains 3-5 days per week

Age: 30, Gender: Male, Weight: 75kg, Height: 175cm, Activity: Moderate, Goal: Maintain
 
Target: ~2500 kcal
Protein: 135g (30%)
Carbs: 250g (40%)
Fat: 83g (30%)

Weight loss for active female

High protein setup for a woman aiming to lose 0.5kg per week

Age: 28, Gender: Female, Weight: 65kg, Height: 162cm, Activity: Active, Goal: Loss, Weekly change: -0.5kg
 
Target: ~1850 kcal
Protein: 143g (40%)
Carbs: 185g (30%)
Fat: 62g (30%)

Keto macro calculation

Very low carb macros for a 90kg man with 15% body fat

Age: 35, Gender: Male, Weight: 90kg, Height: 180cm, Activity: Moderate, Goal: Maintain, Preset: Keto, Body Fat: 15%
 
Target: ~2800 kcal
Protein: 144g (20%)
Carbs: 35g (5%)
Fat: 233g (75%)

Frequently asked questions

How accurate is this macro calculator?

The tool uses the Mifflin-St Jeor formula for BMR (one of the most reliable) combined with standard activity multipliers and the 7700 kcal/kg rule for weight change. Results are excellent starting points, but individual metabolism varies — track your progress and adjust after 2–4 weeks.

What is the best macro ratio for fat loss?

High Protein (≈40/30/30) is often most effective for fat loss as it preserves muscle and increases satiety. This calculator defaults to that style for weight loss goals but lets you choose others.

Do I need to enter body fat percentage?

No, it's optional. Entering it allows the calculator to base protein recommendations on lean body mass, which is more accurate for advanced users or those with known body composition data.

How should I adjust my macros weekly?

Weigh yourself consistently and recalculate every 1–2 weeks. If weight loss stalls, reduce calories by another 200–300 or increase activity. For muscle gain, ensure progressive training and a consistent surplus.

Why are my calculated calories different from other calculators?

Different tools use different BMR formulas (Harris-Benedict vs Mifflin-St Jeor) and activity multipliers. This tool prioritizes Mifflin-St Jeor for better accuracy. Always treat results as estimates.

Can I use this for keto or low-carb diets?

Yes. Select the Keto or Low Carb preset for appropriate ratios (e.g., 75% fat for keto). The tool automatically adjusts carbs down while protecting protein intake.

Are the results suitable for women?

Absolutely. The calculator accounts for gender in BMR calculations and provides appropriate defaults. Women often benefit from slightly higher fat and moderate protein depending on goals.

How do I track these macros daily?

Use any popular nutrition app (MyFitnessPal, Cronometer, etc.) and log your food. Many apps allow saving custom macro targets from this calculator.

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