Sedentary (Little to no exercise)
Lightly Active (Exercise 1-3 days/week)
Moderately Active (Exercise 3-5 days/week)
Very Active (Exercise 6-7 days/week)
Extra Active (Very intense exercise daily, or physical job)
Protein is a vital macronutrient essential for building and repairing tissues, producing enzymes and hormones, and supporting overall health. Determining your optimal daily protein intake depends on several factors, including your body weight, activity level, and fitness goals. This calculator provides an estimate based on commonly accepted nutritional guidelines.
How It Works:
The calculation is primarily based on your body weight and an activity factor, with adjustments for specific fitness goals.
Body Weight: Your weight in kilograms is the foundational metric. Protein needs are often expressed per kilogram of body weight.
Activity Level Multiplier: This factor adjusts your protein needs based on how much you move and exercise.
Sedentary: Typically requires 0.8 – 1.0 grams of protein per kilogram of body weight.
Lightly Active: 1.0 – 1.2 g/kg.
Moderately Active: 1.2 – 1.5 g/kg.
Very Active: 1.5 – 1.8 g/kg.
Extra Active: 1.8 – 2.2 g/kg.
Fitness Goal:
Maintain Muscle: Sticking to the recommended range for your activity level is usually sufficient.
Build Muscle: Higher protein intake (towards the upper end of the activity level range or slightly above) supports muscle protein synthesis.
Lose Fat: Adequate protein intake is crucial during calorie restriction to help preserve lean muscle mass. Often, intakes in the range of 1.6 – 2.2 g/kg are recommended, sometimes even higher depending on the severity of the deficit.
The Calculation Formula (Simplified):
The calculator uses a range based on activity level and goal. A general approach involves multiplying your body weight by a factor derived from these inputs.
Example: A person weighing 70kg who is moderately active (1.2-1.5 g/kg) and aims to build muscle might aim for a range within the higher end of this spectrum.
Lower end: 70 kg * 1.2 g/kg = 84 grams
Higher end: 70 kg * 1.5 g/kg = 105 grams
For muscle building, you might lean towards the higher end or slightly above, aiming for perhaps 105-120 grams.
This calculator aims to provide a practical target within these ranges.
Disclaimer: This calculator provides an estimate for informational purposes only. Consult with a healthcare professional or registered dietitian for personalized dietary advice.
function calculateProtein() {
var bodyWeight = parseFloat(document.getElementById('bodyWeight').value);
var activityLevel = document.getElementById('activityLevel').value;
var goal = document.getElementById('goal').value;
var proteinResultElement = document.getElementById('result');
var resultUnitElement = document.getElementById('result-unit');
// Clear previous results and styling
proteinResultElement.textContent = '–';
proteinResultElement.style.color = '#28a745'; // Default success green
resultUnitElement.textContent = 'grams per day';
// Input validation
if (isNaN(bodyWeight) || bodyWeight <= 0) {
proteinResultElement.textContent = 'Invalid Input';
proteinResultElement.style.color = '#dc3545'; // Error red
return;
}
var minGramsPerKg, maxGramsPerKg;
// Determine grams per kg based on activity level
switch (activityLevel) {
case 'sedentary':
minGramsPerKg = 0.8;
maxGramsPerKg = 1.0;
break;
case 'light':
minGramsPerKg = 1.0;
maxGramsPerKg = 1.2;
break;
case 'moderate':
minGramsPerKg = 1.2;
maxGramsPerKg = 1.5;
break;
case 'very_active':
minGramsPerKg = 1.5;
maxGramsPerKg = 1.8;
break;
case 'extra_active':
minGramsPerKg = 1.8;
maxGramsPerKg = 2.2;
break;
default:
minGramsPerKg = 1.0;
maxGramsPerKg = 1.5;
}
// Adjust range based on fitness goal
if (goal === 'building') {
// Higher end for muscle building
maxGramsPerKg = Math.max(maxGramsPerKg, 1.8); // Ensure we reach at least 1.8
minGramsPerKg = Math.max(minGramsPerKg, 1.4); // Lean towards higher end
} else if (goal === 'losing') {
// Higher end for fat loss to preserve muscle
maxGramsPerKg = Math.max(maxGramsPerKg, 2.0); // Ensure we reach at least 2.0
minGramsPerKg = Math.max(minGramsPerKg, 1.6); // Lean towards higher end
}
// For 'maintenance', the default ranges are usually sufficient.
// Calculate the protein range
var minProtein = bodyWeight * minGramsPerKg;
var maxProtein = bodyWeight * maxGramsPerKg;
// Round to nearest whole number for practical use
minProtein = Math.round(minProtein);
maxProtein = Math.round(maxProtein);
// Display the result
if (minProtein === maxProtein) {
proteinResultElement.textContent = minProtein.toFixed(0);
} else {
proteinResultElement.textContent = minProtein.toFixed(0) + ' – ' + maxProtein.toFixed(0);
}
// Ensure result is visible and styled
proteinResultElement.style.display = 'block';
resultUnitElement.style.display = 'block';
}