Use this calculator to estimate your daily calorie needs and macronutrient breakdown based on your personal data and activity level. This can help you achieve your weight management goals.
Male
Female
kg
lbs
cm
inches
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/week)
Extra Active (very hard exercise/physical job/training twice a day)
Maintain Weight
Lose Weight (approx. 0.5 kg / 1 lb per week)
Gain Weight (approx. 0.5 kg / 1 lb per week)
Your Estimated Daily Needs:
Daily Calories:— kcal
Macronutrient Breakdown:
Protein:— g (—%)
Carbohydrates:— g (—%)
Fats:— g (—%)
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.calc-input-group input[type="number"],
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.calc-input-group input[type="number"],
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}
function calculateCaloriesAndMacros() {
var age = parseFloat(document.getElementById('age').value);
var gender = document.getElementById('gender').value;
var weight = parseFloat(document.getElementById('weight').value);
var weightUnit = document.getElementById('weightUnit').value;
var height = parseFloat(document.getElementById('height').value);
var heightUnit = document.getElementById('heightUnit').value;
var activityLevel = document.getElementById('activityLevel').value;
var goal = document.getElementById('goal').value;
// Input validation
if (isNaN(age) || age <= 0 || isNaN(weight) || weight <= 0 || isNaN(height) || height <= 0) {
document.getElementById('dailyCalories').innerText = 'Invalid Input';
document.getElementById('proteinGrams').innerText = '–';
document.getElementById('carbGrams').innerText = '–';
document.getElementById('fatGrams').innerText = '–';
document.getElementById('proteinPercent').innerText = '–';
document.getElementById('carbPercent').innerText = '–';
document.getElementById('fatPercent').innerText = '–';
alert('Please enter valid positive numbers for Age, Weight, and Height.');
return;
}
// Convert weight to kg
if (weightUnit === 'lbs') {
weight = weight * 0.453592; // 1 lb = 0.453592 kg
}
// Convert height to cm
if (heightUnit === 'inches') {
height = height * 2.54; // 1 inch = 2.54 cm
}
var bmr; // Basal Metabolic Rate
// 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 activityFactor;
switch (activityLevel) {
case 'sedentary':
activityFactor = 1.2;
break;
case 'light':
activityFactor = 1.375;
break;
case 'moderate':
activityFactor = 1.55;
break;
case 'very':
activityFactor = 1.725;
break;
case 'extra':
activityFactor = 1.9;
break;
default:
activityFactor = 1.2; // Default to sedentary
}
var tdee = bmr * activityFactor; // Total Daily Energy Expenditure
var dailyCalories;
if (goal === 'lose') {
dailyCalories = tdee – 500; // Aim for ~0.5 kg/1 lb weight loss per week
} else if (goal === 'gain') {
dailyCalories = tdee + 500; // Aim for ~0.5 kg/1 lb weight gain per week
} else { // maintain
dailyCalories = tdee;
}
// Ensure calories don't go too low for safety
if (dailyCalories < 1200 && gender === 'female') dailyCalories = 1200;
if (dailyCalories < 1500 && gender === 'male') dailyCalories = 1500;
// Macronutrient breakdown (example percentages)
var proteinPercent = 0.25; // 25%
var fatPercent = 0.30; // 30%
var carbPercent = 1 – proteinPercent – fatPercent; // 45%
var proteinCalories = dailyCalories * proteinPercent;
var fatCalories = dailyCalories * fatPercent;
var carbCalories = dailyCalories * carbPercent;
var proteinGrams = proteinCalories / 4; // 4 calories per gram of protein
var fatGrams = fatCalories / 9; // 9 calories per gram of fat
var carbGrams = carbCalories / 4; // 4 calories per gram of carbohydrates
// Display results
document.getElementById('dailyCalories').innerText = Math.round(dailyCalories);
document.getElementById('proteinGrams').innerText = Math.round(proteinGrams);
document.getElementById('carbGrams').innerText = Math.round(carbGrams);
document.getElementById('fatGrams').innerText = Math.round(fatGrams);
document.getElementById('proteinPercent').innerText = Math.round(proteinPercent * 100);
document.getElementById('carbPercent').innerText = Math.round(carbPercent * 100);
document.getElementById('fatPercent').innerText = Math.round(fatPercent * 100);
}
Understanding Your Daily Calorie and Macronutrient Needs
Achieving your health and fitness goals, whether it's weight loss, muscle gain, or simply maintaining a healthy lifestyle, often starts with understanding your body's energy requirements. This involves two key components: calories and macronutrients.
What are Calories?
A calorie is a unit of energy. In nutrition, it refers to the energy your body gets from food and drinks. Your body needs calories to perform all its functions, from breathing and thinking to exercising and digesting food. The number of calories you consume versus the number you burn determines whether you gain, lose, or maintain weight.
Basal Metabolic Rate (BMR): This is the number of calories your body needs to perform basic, life-sustaining functions while at rest (e.g., breathing, circulation, cell production).
Total Daily Energy Expenditure (TDEE): This is your BMR plus the calories you burn through physical activity and the thermic effect of food (energy used for digestion).
What are Macronutrients?
Macronutrients, often shortened to "macros," are the nutrients your body needs in large amounts to provide energy and support various bodily functions. There are three primary macronutrients:
Proteins: Essential for building and repairing tissues, making enzymes and hormones, and supporting immune function. They provide 4 calories per gram. Good sources include meat, fish, eggs, dairy, legumes, and nuts.
Carbohydrates: The body's primary source of energy. They are broken down into glucose, which fuels your brain and muscles. They also provide 4 calories per gram. Found in grains, fruits, vegetables, and legumes.
Fats: Crucial for hormone production, nutrient absorption (especially fat-soluble vitamins), and protecting organs. They are the most energy-dense macronutrient, providing 9 calories per gram. Sources include oils, nuts, seeds, avocados, and fatty fish.
How Our Calculator Works
Our Daily Calorie & Macro Calculator uses established scientific formulas to estimate your needs:
BMR Calculation: It first calculates your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation, which is widely considered one of the most accurate BMR formulas. This formula takes into account your age, gender, weight, and height.
Activity Level Adjustment: Your BMR is then multiplied by an activity factor based on your selected activity level (from sedentary to extra active) to determine your Total Daily Energy Expenditure (TDEE).
Goal Adjustment: Finally, your TDEE is adjusted based on your weight goal (maintain, lose, or gain). For weight loss or gain, a common adjustment of +/- 500 calories per day is used, which typically corresponds to a change of approximately 0.5 kg (1 lb) per week.
Macronutrient Breakdown: The calculator then distributes your total daily calories into recommended percentages for protein, carbohydrates, and fats, and converts these into grams. A common distribution is 25% protein, 45% carbohydrates, and 30% fats, but these can be customized based on individual dietary preferences or specific goals.
Interpreting Your Results
The results from this calculator provide a personalized estimate of your daily calorie and macronutrient needs. Use these numbers as a starting point for planning your diet. Remember:
Calories: If your goal is weight loss, consuming slightly fewer calories than your estimated daily need is crucial. For weight gain, consume slightly more. For maintenance, aim to match your intake to your expenditure.
Macros: The macronutrient breakdown helps you understand the composition of your diet. For example, if you're building muscle, you might prioritize higher protein intake. If you're an endurance athlete, carbohydrates will be a significant focus.
Flexibility: These are guidelines, not strict rules. Your body's needs can fluctuate based on daily activity, stress, and other factors. Listen to your body and adjust as needed.
Important Considerations
While this calculator provides a valuable estimate, it's important to remember that it's a generalized tool. Individual results can vary due to metabolism, genetics, body composition, and other factors. For personalized dietary advice, especially if you have underlying health conditions or specific athletic goals, always consult with a qualified healthcare professional or a registered dietitian.