Calculate your optimal daily protein needs based on science
Male
Female
Sedentary (Office job, little exercise)
Lightly Active (Light exercise 1-3 days/week)
Moderately Active (Moderate exercise 3-5 days/week)
Very Active (Hard exercise 6-7 days/week)
Extra Active (Very hard exercise & physical job)
Maintenance (Keep current weight)
Weight Loss (Preserve muscle while cutting)
Muscle Gain (Build new tissue)
Your Daily Targets:
Daily Protein0g
Protein Calories0
Protein Ratio0%
Understanding Your Protein Requirements
Protein is the building block of life. Whether you are looking to lose fat, build muscle, or simply maintain your current health, consuming the correct amount of protein is critical. This calculator uses the Mifflin-St Jeor equation to estimate your Resting Metabolic Rate (RMR) and adjusts your protein intake based on your activity level and physical goals.
Why Protein Matters
Protein is comprised of amino acids that repair muscle tissue, support immune function, and produce essential hormones and enzymes. Unlike carbohydrates and fats, the body does not store protein in large reserves, making consistent daily intake vital.
How the Calculation Works
We use a multi-step clinical approach to determine your needs:
Basal Metabolic Rate (BMR): The energy your body needs at rest.
Total Daily Energy Expenditure (TDEE): Your BMR multiplied by your physical activity level.
Goal Adjustment:
Maintenance: 1.2g to 1.5g of protein per kg of body weight.
Weight Loss: 1.8g to 2.2g of protein per kg to prevent muscle wasting during a calorie deficit.
Muscle Gain: 1.6g to 2.0g of protein per kg to provide the substrate for new muscle synthesis.
Practical Examples
Consider these two scenarios to see how variables change the output:
Example 1: The Sedentary Office Worker
A 70kg male who is sedentary and wants to maintain weight. His requirement would be approximately 84g to 105g of protein per day. This ensures basic metabolic function and tissue repair without excess calorie intake.
Example 2: The Active Bodybuilder
An 85kg female who trains 5 days a week and wants to gain muscle. Her requirement would jump to 153g to 170g of protein per day. The higher intensity and growth goal necessitate a significantly higher amino acid pool.
Factors That Influence Your Needs
While this calculator provides a scientifically-backed starting point, individual needs can vary based on:
Body Composition: Individuals with higher muscle mass require more protein to maintain that tissue.
Age: Sarcopenia (age-related muscle loss) often requires older adults to consume higher protein ratios (1.2g+/kg) even if sedentary.
Injury Recovery: If you are recovering from surgery or a sports injury, your protein needs increase significantly to facilitate tissue repair.
function calculateProtein() {
var gender = document.getElementById("calcGender").value;
var age = parseFloat(document.getElementById("calcAge").value);
var weight = parseFloat(document.getElementById("calcWeight").value);
var height = parseFloat(document.getElementById("calcHeight").value);
var activity = parseFloat(document.getElementById("calcActivity").value);
var goal = document.getElementById("calcGoal").value;
if (isNaN(age) || isNaN(weight) || isNaN(height)) {
alert("Please enter valid numbers for age, weight, and height.");
return;
}
// Calculate BMR (Mifflin-St Jeor)
var bmr;
if (gender === "male") {
bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5;
} else {
bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161;
}
var tdee = bmr * activity;
var proteinGrams = 0;
var recommendation = "";
// Calculation logic based on goals (grams per kg)
if (goal === "maintain") {
proteinGrams = weight * 1.4;
recommendation = "You are in the maintenance zone. Aim for balanced meals containing 25-30g of protein each.";
} else if (goal === "lose") {
// Higher protein helps spare muscle during deficit
proteinGrams = weight * 2.0;
recommendation = "In a calorie deficit, high protein is crucial to prevent muscle loss. Prioritize lean sources like chicken breast, white fish, and egg whites.";
} else if (goal === "gain") {
proteinGrams = weight * 1.8;
recommendation = "To build muscle, ensure you are also in a slight calorie surplus. Protein should be spread evenly throughout 4-5 meals.";
}
var proteinCalories = proteinGrams * 4;
var proteinRatio = Math.round((proteinCalories / tdee) * 100);
// Display Results
document.getElementById("resultGrams").innerHTML = Math.round(proteinGrams) + "g";
document.getElementById("resultCalories").innerHTML = Math.round(proteinCalories) + " kcal";
document.getElementById("resultRatio").innerHTML = proteinRatio + "%";
document.getElementById("recommendationText").innerHTML = "Expert Tip: " + recommendation;
document.getElementById("proteinResult").style.display = "block";
// Scroll to results
document.getElementById("proteinResult").scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}