Estimate your daily caloric needs based on your metabolic rate and activity level.
Male
Female
Sedentary (little to 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)
Estimated Daily Caloric Needs
— kcal
Understanding Calorie Needs
Calculating your daily calorie needs is a fundamental step towards managing your weight and maintaining a healthy lifestyle. Your body requires a certain amount of energy (calories) each day to function, from basic metabolic processes to physical activity. This calculator estimates your Basal Metabolic Rate (BMR) and then adjusts it based on your activity level to provide a total daily energy expenditure (TDEE).
Basal Metabolic Rate (BMR)
BMR is the number of calories your body burns at rest to maintain vital functions such as breathing, circulation, and cell production. It's the minimum energy required to keep you alive. The most common formulas used to estimate BMR are the Mifflin-St Jeor equation and the Harris-Benedict equation. This calculator uses the Mifflin-St Jeor equation, which is generally considered more accurate:
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 multiplied by an activity factor to estimate your TDEE, which represents the total calories you burn throughout the day, including all physical activity. The activity factors are as follows:
Sedentary: BMR × 1.2
Lightly Active: BMR × 1.375
Moderately Active: BMR × 1.55
Very Active: BMR × 1.725
Extra Active: BMR × 1.9
How to Use This Calculator
Enter your current weight, height, age, gender, and select your typical weekly activity level. The calculator will then provide an estimate of the calories you need to consume daily to maintain your current weight.
Important Considerations
This calculator provides an estimate. Individual metabolic rates can vary due to genetics, body composition (muscle mass vs. fat mass), hormonal factors, and other health conditions. For precise dietary and weight management plans, it is always recommended to consult with a healthcare professional or a registered dietitian.
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 = document.getElementById("activityLevel").value;
var resultValueElement = document.getElementById("result-value");
var explanationTextElement = document.getElementById("explanation-text");
if (isNaN(weight) || isNaN(height) || isNaN(age) || weight <= 0 || height <= 0 || age <= 0) {
resultValueElement.innerText = "Invalid Input";
explanationTextElement.innerText = "Please enter valid positive numbers for weight, height, and age.";
return;
}
var bmr = 0;
if (gender === "male") {
bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5;
} else { // female
bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161;
}
var activityMultiplier = 0;
switch (activityLevel) {
case "sedentary":
activityMultiplier = 1.2;
break;
case "lightly_active":
activityMultiplier = 1.375;
break;
case "moderately_active":
activityMultiplier = 1.55;
break;
case "very_active":
activityMultiplier = 1.725;
break;
case "extra_active":
activityMultiplier = 1.9;
break;
default:
activityMultiplier = 1.2; // Default to sedentary if somehow invalid
}
var tdee = bmr * activityMultiplier;
var roundedTdee = Math.round(tdee);
resultValueElement.innerText = roundedTdee + " kcal";
var explanation = "";
if (gender === "male") {
explanation += "Using Mifflin-St Jeor for Men: BMR = (10 * " + weight + ") + (6.25 * " + height + ") – (5 * " + age + ") + 5 = " + Math.round(bmr) + " kcal. ";
} else {
explanation += "Using Mifflin-St Jeor for Women: BMR = (10 * " + weight + ") + (6.25 * " + height + ") – (5 * " + age + ") – 161 = " + Math.round(bmr) + " kcal. ";
}
explanation += "Activity Factor (" + activityLevel.replace('_', ' ') + "): " + activityMultiplier + ". TDEE = BMR * Activity Factor = " + Math.round(bmr) + " * " + activityMultiplier + " = " + roundedTdee + " kcal.";
explanationTextElement.innerText = explanation;
}