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 & physical job)
Maintain Weight
Lose Weight (slight deficit)
Gain Weight (slight surplus)
Your Daily Nutritional Targets
Total Daily Calories: N/A
Understanding Your Calorie and Macronutrient Needs
Calculating your daily calorie and macronutrient needs is fundamental to achieving your health and fitness goals, whether you aim to lose weight, gain muscle, or simply maintain a healthy lifestyle. This calculator provides personalized estimates based on the Mifflin-St Jeor equation, which is widely considered one of the most accurate formulas for estimating Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).
Basal Metabolic Rate (BMR)
Your BMR is the number of calories your body burns at rest to maintain basic life functions, such as breathing, circulation, and cell production. The Mifflin-St Jeor equation is used 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)
Your TDEE is the total number of calories you burn in a day, accounting for your BMR and your physical activity level. TDEE is calculated by multiplying your BMR by an activity factor:
Sedentary: BMR x 1.2
Lightly Active: BMR x 1.375
Moderately Active: BMR x 1.55
Very Active: BMR x 1.725
Extra Active: BMR x 1.9
Calorie Adjustment for Goals
To achieve your weight goals, your TDEE is adjusted:
These adjustments are typical starting points. Individual metabolism and adherence can affect results.
Macronutrient Distribution
Macronutrients (macros) are carbohydrates, proteins, and fats. They provide energy and are essential for bodily functions. A common and effective distribution for general health and fitness is:
Protein: 30% of total calories
Fats: 30% of total calories
Carbohydrates: 40% of total calories
These percentages are then converted into grams, knowing that:
1 gram of protein = 4 calories
1 gram of fat = 9 calories
1 gram of carbohydrate = 4 calories
For example, if your target is 2000 calories:
Protein: (2000 * 0.30) / 4 = 150 grams
Fats: (2000 * 0.30) / 9 = 67 grams
Carbohydrates: (2000 * 0.40) / 4 = 200 grams
How to Use This Calculator
Enter your age, gender, weight, height, select your activity level, and state your weight goal. The calculator will then estimate your daily calorie needs and break down your macronutrient targets. Remember that these are estimates, and individual needs may vary. Consulting with a healthcare professional or registered dietitian is recommended for personalized advice.
function calculateMacros() {
var age = parseFloat(document.getElementById("age").value);
var gender = document.getElementById("gender").value;
var weight = parseFloat(document.getElementById("weight").value);
var height = parseFloat(document.getElementById("height").value);
var activityLevel = document.getElementById("activityLevel").value;
var goal = document.getElementById("goal").value;
var bmr = 0;
if (isNaN(age) || isNaN(weight) || isNaN(height)) {
alert("Please enter valid numbers for age, weight, and height.");
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;
}
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 something goes wrong
}
var tdee = bmr * activityMultiplier;
var targetCalories = tdee;
// Adjust calories based on goal
if (goal === "lose") {
targetCalories = tdee – 500;
} else if (goal === "gain") {
targetCalories = tdee + 300;
}
// Ensure calories are not unrealistically low or high
if (targetCalories 4000) targetCalories = 4000;
// Calculate Macronutrients
var proteinCalories = targetCalories * 0.30;
var fatCalories = targetCalories * 0.30;
var carbCalories = targetCalories * 0.40;
var proteinGrams = proteinCalories / 4;
var fatGrams = fatCalories / 9;
var carbGrams = carbCalories / 4;
// Display Results
document.getElementById("totalCalories").innerText = "Total Daily Calories: " + Math.round(targetCalories) + " kcal";
var macroBreakdownHtml = '