Sedentary (little or no 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)
Your Daily Calorie Needs
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Understanding Your Daily Calorie Needs
Calculating your daily calorie needs is a fundamental step towards achieving your health and fitness goals, whether that's weight loss, weight maintenance, or weight gain. The number of calories you need each day depends on several factors including your age, sex, weight, height, and activity level. This calculator uses the Mifflin-St Jeor equation, which is widely considered one of the most accurate formulas for estimating Basal Metabolic Rate (BMR) – the number of calories your body burns at rest.
Basal Metabolic Rate (BMR) Calculation
The Mifflin-St Jeor equation estimates your BMR as follows:
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
Total Daily Energy Expenditure (TDEE)
Once your BMR is calculated, it's adjusted by an activity factor to determine your Total Daily Energy Expenditure (TDEE). TDEE represents the total number of calories you burn in a day, including all physical activity. The activity factors used in this calculator are:
Extra Active: 1.9 (very hard exercise, physical job or training)
The formula for TDEE is: TDEE = BMR * Activity Factor
How to Use This Calculator
To get your estimated daily calorie needs:
Enter your age in years.
Select your gender.
Input your current weight in kilograms (kg).
Input your height in centimeters (cm).
Choose the option that best describes your weekly physical activity level.
Click "Calculate Daily Calories".
The result will show you an estimate of the calories you need to consume daily to maintain your current weight.
Factors Influencing Calorie Needs
It's important to remember that this calculator provides an estimate. Individual calorie needs can vary due to genetics, muscle mass, hormonal factors, and specific health conditions. For personalized dietary advice, consult with a healthcare professional or a registered dietitian.
function calculateCalories() {
var age = document.getElementById("age").value;
var gender = document.getElementById("gender").value;
var weight = document.getElementById("weight").value;
var height = document.getElementById("height").value;
var activityLevel = document.getElementById("activityLevel").value;
var resultElement = document.getElementById("result");
// Input validation
if (age === "" || weight === "" || height === "" || isNaN(age) || isNaN(weight) || isNaN(height) || age <= 0 || weight <= 0 || height <= 0) {
resultElement.textContent = "Please enter valid numbers for age, weight, and height.";
return;
}
var bmr;
if (gender === "male") {
bmr = (10 * parseFloat(weight)) + (6.25 * parseFloat(height)) – (5 * parseFloat(age)) + 5;
} else { // female
bmr = (10 * parseFloat(weight)) + (6.25 * parseFloat(height)) – (5 * parseFloat(age)) – 161;
}
var tdee = bmr * parseFloat(activityLevel);
resultElement.textContent = Math.round(tdee) + " calories";
}