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)
Estimated Daily Caloric Needs:
Understanding Precision Nutrition and Caloric Needs
Precision nutrition is an emerging field that aims to personalize dietary recommendations based on an individual's unique biological makeup, lifestyle, and health goals. Unlike generic dietary advice, it seeks to optimize health outcomes by tailoring macronutrient ratios, micronutrient intake, and meal timing to the individual.
A foundational aspect of precision nutrition is understanding an individual's daily caloric needs. This is often estimated using formulas that consider key physiological factors. The most common approach involves calculating Basal Metabolic Rate (BMR) and then multiplying it by an activity factor to estimate Total Daily Energy Expenditure (TDEE).
The Harris-Benedict Equation (Revised)
This calculator utilizes a revised version of the Harris-Benedict equation, a widely recognized method for estimating BMR. The formulas are as follows:
For Men: BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) – (5.677 × age in years)
For Women: BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) – (4.330 × age in years)
Total Daily Energy Expenditure (TDEE)
Once BMR is calculated, it's multiplied by an activity factor to account for the calories burned through daily activities and exercise. This gives us the TDEE, which represents the total number of calories an individual needs to maintain their current body weight.
TDEE = BMR × Activity Factor
The activity factors used in this calculator are standard estimations:
1.2: Sedentary (little to no exercise)
1.375: Lightly Active (exercise 1-3 days/week)
1.55: Moderately Active (exercise 3-5 days/week)
1.725: Very Active (exercise 6-7 days/week)
1.9: Extra Active (very intense exercise daily, or physical job)
How This Calculator Works
This calculator takes your age, gender, weight, height, and chosen activity level to compute your estimated daily caloric needs (TDEE). This figure is a crucial starting point for developing a personalized nutrition plan, whether your goal is weight management, athletic performance, or general health improvement.
Disclaimer: This calculator provides an estimation. For personalized dietary advice, consult with a registered dietitian or a qualified healthcare professional. Individual metabolic rates can vary significantly.
function calculateNutrition() {
var age = parseFloat(document.getElementById("age").value);
var gender = document.getElementById("gender").value;
var weightKg = parseFloat(document.getElementById("weightKg").value);
var heightCm = parseFloat(document.getElementById("heightCm").value);
var activityLevel = parseFloat(document.getElementById("activityLevel").value);
var bmr = 0;
var formulaUsed = "";
// Validate inputs
if (isNaN(age) || isNaN(weightKg) || isNaN(heightCm) || isNaN(activityLevel) || age <= 0 || weightKg <= 0 || heightCm <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
// Calculate BMR based on gender
if (gender === "male") {
bmr = 88.362 + (13.397 * weightKg) + (4.799 * heightCm) – (5.677 * age);
formulaUsed = "BMR (Male) = 88.362 + (13.397 × W) + (4.799 × H) – (5.677 × A)";
} else { // female
bmr = 447.593 + (9.247 * weightKg) + (3.098 * heightCm) – (4.330 * age);
formulaUsed = "BMR (Female) = 447.593 + (9.247 × W) + (3.098 × H) – (4.330 × A)";
}
// Calculate TDEE
var tdee = bmr * activityLevel;
// Display results
document.getElementById("resultValue").innerText = Math.round(tdee) + " kcal";
document.getElementById("resultFormula").innerText = formulaUsed + " → TDEE = BMR × Activity Factor";
document.getElementById("resultExplanation").innerText = "This is your estimated daily caloric intake to maintain current weight.";
document.getElementById("result").style.display = "block";
}