Macro Calculator

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Macro Calculator
Weight Loss (Deficit)Maintenance (TDEE)Muscle Gain (Surplus)
MaleFemale
Sedentary (Office job)Lightly Active (1-3 days/week)Moderately Active (3-5 days/week)Very Active (6-7 days/week)Extra Active (Physical job/2x workouts)
Your Daily Targets:
Calories
0 kcal
Protein
0g
Carbs
0g
Fats
0g
function calculateMacros(){var age=parseFloat(document.getElementById('age').value);var weightLb=parseFloat(document.getElementById('weight').value);var heightIn=parseFloat(document.getElementById('height').value);var gender=document.getElementById('gender').value;var activity=parseFloat(document.getElementById('activity').value);var goal=document.getElementById('macro_goal').value;var highProt=document.getElementById('high_protein').checked;if(isNaN(age)||isNaN(weightLb)||isNaN(heightIn)){alert('Please fill in all numerical fields correctly.');return;}var wKg=weightLb*0.453592;var hCm=heightIn*2.54;var bmr=0;if(gender==='male'){bmr=(10*wKg)+(6.25*hCm)-(5*age)+5;}else{bmr=(10*wKg)+(6.25*hCm)-(5*age)-161;}var tdee=bmr*activity;var targetCals=tdee;if(goal==='lose'){targetCals=tdee-500;}else if(goal==='gain'){targetCals=tdee+300;}var p=0;var f=0;var c=0;if(highProt){p=weightLb;}else{p=(targetCals*0.25)/4;}f=(targetCals*0.25)/9;c=(targetCals-(p*4)-(f*9))/4;document.getElementById('resCal').innerHTML=Math.round(targetCals);document.getElementById('resProt').innerHTML=Math.round(p);document.getElementById('resFat').innerHTML=Math.round(f);document.getElementById('resCarb').innerHTML=Math.round(c);}

Calculator Use

The macro calculator is an essential tool for anyone looking to optimize their nutrition for specific fitness goals, whether that is fat loss, muscle gain, or weight maintenance. By analyzing your physical attributes and activity levels, this calculator provides a personalized breakdown of the three primary macronutrients: proteins, carbohydrates, and fats.

To get the most accurate results, ensure you select your correct activity level and choose a goal that aligns with your current training cycle. This calculator uses the Mifflin-St Jeor equation, widely considered the most accurate formula for estimating basal metabolic rate (BMR).

Basal Metabolic Rate (BMR)
The number of calories your body burns at rest just to keep vital organs functioning.
Total Daily Energy Expenditure (TDEE)
The total calories you burn in a day, including physical activity and the thermic effect of food.
Macronutrients (Macros)
Protein, carbohydrates, and fats. These provide the energy (calories) your body needs.

How It Works

When you use the macro calculator, it performs several sequential calculations to arrive at your final numbers. First, it determines your BMR based on your sex, age, weight, and height. Next, it applies an activity multiplier to find your TDEE.

Mifflin-St Jeor Formula (Male) = (10 × weight in kg) + (6.25 × height in cm) – (5 × age) + 5

  • Protein: Essential for muscle repair and growth. Contains 4 calories per gram.
  • Fats: Vital for hormone production and brain health. Contains 9 calories per gram.
  • Carbohydrates: The body's primary energy source. Contains 4 calories per gram.

Calculation Example

Example: A 30-year-old male weighing 180 lbs (81.6 kg) at 5'10" (177.8 cm) who is moderately active and wants to maintain his weight.

Step-by-step solution:

  1. BMR Calculation: (10 × 81.6) + (6.25 × 177.8) – (5 × 30) + 5 = 1,782 calories.
  2. TDEE Calculation: 1,782 × 1.55 (Moderately Active) = 2,762 calories.
  3. Protein Target: 180 lbs = 180g (720 calories).
  4. Fat Target: 25% of 2,762 = 690 calories / 9 = 77g.
  5. Carb Target: (2,762 – 720 – 690) = 1,352 calories / 4 = 338g.
  6. Final Macros: 2,762 Calories | 180g Protein | 338g Carbs | 77g Fat.

Common Questions

What is the most important macro?

While all three are essential, protein is often prioritized in a macro calculator for those exercising regularly, as it is the building block of muscle tissue and keeps you feeling full during a calorie deficit.

Can I change my carb and fat ratio?

Yes. Once you have your protein and total calorie targets, the split between carbs and fats can be adjusted based on personal preference and how your body responds to different energy sources. Some people prefer "Low Carb/High Fat," while athletes often prefer "High Carb/Low Fat."

How often should I recalculate my macros?

It is recommended to recalculate your macros every time you lose or gain 5-10 pounds, or if your activity level changes significantly. As your body weight changes, your BMR and TDEE will also shift, requiring updated targets.

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