Estimate your daily calorie needs for weight management.
Male
Female
Sedentary (little or no exercise)
Lightly Active (light exercise/sports 1-3 days/week)
Moderately Active (moderate exercise/sports 3-5 days/week)
Very Active (hard exercise/sports 6-7 days a week)
Extra Active (very hard exercise/sports & physical job or 2x training)
Your Estimated Daily Calorie Needs:
Understanding Your Daily Calorie Needs
Calculating your daily calorie needs is a fundamental step in managing your weight, whether your goal is to lose, maintain, or gain. The "Fitness Pal Calorie Calculator" helps estimate this by considering several key personal factors. The core of this calculation relies on estimating your Basal Metabolic Rate (BMR) and then multiplying it by an activity factor.
Basal Metabolic Rate (BMR)
BMR is the number of calories your body burns at rest to maintain basic life-sustaining functions like breathing, circulation, and cell production. It's the minimum energy your body requires. The most common formulas for BMR are the Harris-Benedict equation (revised) and the Mifflin-St Jeor equation. For this calculator, we utilize the Mifflin-St Jeor equation, which is widely considered more accurate for most people.
Mifflin-St Jeor Equation:
For Men: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
For Women: BMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
In the JavaScript code, these formulas are implemented to calculate your BMR based on the inputs you provide.
Total Daily Energy Expenditure (TDEE)
Once your BMR is calculated, it's adjusted for your daily activity level to determine your Total Daily Energy Expenditure (TDEE). TDEE represents the total number of calories you burn in a 24-hour period, including exercise and general daily movement. This is achieved by multiplying your BMR by an activity factor.
Activity Factors:
1.2: Sedentary (little or no exercise)
1.375: Lightly Active (light exercise/sports 1-3 days/week)
1.55: Moderately Active (moderate exercise/sports 3-5 days/week)
1.725: Very Active (hard exercise/sports 6-7 days a week)
1.9: Extra Active (very hard exercise/sports & physical job or 2x training)
TDEE = BMR × Activity Factor
Using Your Calorie Estimate
The result from this calculator provides an estimate of the calories you need to consume daily to maintain your current weight.
To Lose Weight: You typically need to consume fewer calories than your TDEE. A common recommendation is to create a deficit of 500-1000 calories per day, which can lead to a weight loss of approximately 1-2 pounds per week.
To Gain Weight: You need to consume more calories than your TDEE. A surplus of 250-500 calories per day can lead to a healthy weight gain of about 0.5-1 pound per week.
Important Note: This calculator provides an estimate. Individual metabolic rates can vary. It's always recommended to consult with a healthcare professional or a registered dietitian for personalized advice tailored to your specific health and fitness goals.
function calculateCalories() {
var weight = parseFloat(document.getElementById("weight").value);
var height = parseFloat(document.getElementById("height").value);
var age = parseFloat(document.getElementById("age").value);
var gender = document.getElementById("gender").value;
var activityLevel = parseFloat(document.getElementById("activityLevel").value);
var bmr = 0;
var tdee = 0;
var resultDisplay = document.getElementById("result");
var resultValueDisplay = document.getElementById("result-value");
var goalMessageDisplay = document.getElementById("goal-message");
// Validate inputs
if (isNaN(weight) || isNaN(height) || isNaN(age) || weight <= 0 || height <= 0 || age <= 0) {
alert("Please enter valid positive numbers for weight, height, and age.");
resultDisplay.style.display = 'none';
return;
}
// Calculate BMR using Mifflin-St Jeor equation
if (gender === "male") {
bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5;
} else { // female
bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161;
}
// Calculate TDEE
tdee = bmr * activityLevel;
// Display the result
resultValueDisplay.innerHTML = Math.round(tdee) + " kcal";
goalMessageDisplay.innerHTML = "This is your estimated daily calorie intake to maintain your current weight.";
resultDisplay.style.display = 'block';
}