Daily Calorie Needs Calculator
Use this calculator to estimate your daily calorie needs based on your age, gender, weight, height, and activity level. Understanding your Total Daily Energy Expenditure (TDEE) is crucial whether you're looking to maintain, lose, or gain weight.
.calorie-calculator-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 700px;
margin: 20px auto;
padding: 25px;
border: 1px solid #e0e0e0;
border-radius: 10px;
background-color: #fdfdfd;
box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
color: #333;
}
.calorie-calculator-container h2 {
text-align: center;
color: #2c3e50;
margin-bottom: 20px;
font-size: 1.8em;
}
.calorie-calculator-container p {
margin-bottom: 25px;
line-height: 1.6;
color: #555;
text-align: center;
}
.calculator-form .form-group {
margin-bottom: 18px;
display: flex;
flex-wrap: wrap;
align-items: center;
}
.calculator-form label {
flex: 0 0 150px;
margin-right: 15px;
font-weight: bold;
color: #444;
font-size: 0.95em;
}
.calculator-form input[type="number"] {
flex: 1;
padding: 10px 12px;
border: 1px solid #ccc;
border-radius: 5px;
max-width: 150px;
box-sizing: border-box;
font-size: 1em;
}
.calculator-form input[type="radio"] {
margin-left: 15px;
margin-right: 5px;
transform: scale(1.1);
}
.calculator-form select {
flex: 1;
padding: 10px 12px;
border: 1px solid #ccc;
border-radius: 5px;
background-color: #fff;
max-width: 300px;
font-size: 1em;
cursor: pointer;
}
.calculator-form button {
display: block;
width: 100%;
padding: 12px 20px;
background-color: #28a745;
color: white;
border: none;
border-radius: 5px;
font-size: 1.1em;
font-weight: bold;
cursor: pointer;
transition: background-color 0.3s ease, transform 0.2s ease;
margin-top: 25px;
}
.calculator-form button:hover {
background-color: #218838;
transform: translateY(-2px);
}
.calculator-result {
margin-top: 30px;
padding: 20px;
border: 1px solid #d4edda;
background-color: #e9f7ef;
border-radius: 8px;
font-size: 1.1em;
color: #155724;
line-height: 1.8;
text-align: center;
}
.calculator-result h3 {
color: #218838;
margin-top: 0;
margin-bottom: 15px;
font-size: 1.5em;
}
.calculator-result p {
margin-bottom: 10px;
color: #155724;
}
.calculator-result strong {
color: #0f5132;
}
@media (max-width: 600px) {
.calorie-calculator-container {
padding: 15px;
}
.calculator-form label {
flex: 1 1 100%;
margin-bottom: 5px;
}
.calculator-form input[type="number"],
.calculator-form select {
max-width: 100%;
}
.calculator-form .form-group {
flex-direction: column;
align-items: flex-start;
}
.calculator-form input[type="radio"] {
margin-left: 0;
margin-right: 10px;
}
}
function calculateCalories() {
var age = parseFloat(document.getElementById('age').value);
var weight = parseFloat(document.getElementById('weight').value);
var height = parseFloat(document.getElementById('height').value);
var genderMale = document.getElementById('genderMale').checked;
var genderFemale = document.getElementById('genderFemale').checked;
var gender = genderMale ? 'male' : 'female';
var weightUnitKg = document.getElementById('weightUnitKg').checked;
var weightUnitLbs = document.getElementById('weightUnitLbs').checked;
var currentWeightUnit = weightUnitKg ? 'kg' : 'lbs';
var heightUnitCm = document.getElementById('heightUnitCm').checked;
var heightUnitInches = document.getElementById('heightUnitInches').checked;
var currentHeightUnit = heightUnitCm ? 'cm' : 'inches';
var activityLevel = document.getElementById('activityLevel').value;
var goalMaintain = document.getElementById('goalMaintain').checked;
var goalLose = document.getElementById('goalLose').checked;
var goalGain = document.getElementById('goalGain').checked;
var goal = goalMaintain ? 'maintain' : (goalLose ? 'lose' : 'gain');
var resultDiv = document.getElementById('calorieResult');
resultDiv.innerHTML = "; // Clear previous results
// Input validation
if (isNaN(age) || age <= 0 || isNaN(weight) || weight <= 0 || isNaN(height) || height <= 0) {
resultDiv.innerHTML = 'Please enter valid positive numbers for age, weight, and height.';
return;
}
// Convert weight to kg if lbs
var weightKg = weight;
if (currentWeightUnit === 'lbs') {
weightKg = weight * 0.453592;
}
// Convert height to cm if inches
var heightCm = height;
if (currentHeightUnit === 'inches') {
heightCm = height * 2.54;
}
var bmr; // Basal Metabolic Rate (Mifflin-St Jeor Equation)
if (gender === 'male') {
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) + 5;
} else { // female
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) – 161;
}
var activityMultiplier;
switch (activityLevel) {
case 'sedentary':
activityMultiplier = 1.2;
break;
case 'light':
activityMultiplier = 1.375;
break;
case 'moderate':
activityMultiplier = 1.55;
break;
case 'very':
activityMultiplier = 1.725;
break;
case 'extra':
activityMultiplier = 1.9;
break;
default:
activityMultiplier = 1.55; // Default to moderate
}
var tdee = bmr * activityMultiplier; // Total Daily Energy Expenditure
var targetCalories = tdee;
var goalDescription = "to maintain your current weight.";
if (goal === 'lose') {
targetCalories = tdee – 500; // ~500 calorie deficit for ~1 lb/week loss
goalDescription = "to lose approximately 1 lb (0.45 kg) per week.";
} else if (goal === 'gain') {
targetCalories = tdee + 500; // ~500 calorie surplus for ~1 lb/week gain
goalDescription = "to gain approximately 1 lb (0.45 kg) per week.";
}
resultDiv.innerHTML =
'
Your Estimated Daily Calorie Needs:
' +
'Your Basal Metabolic Rate (BMR):
' + Math.round(bmr) + ' calories/day' +
'Your Total Daily Energy Expenditure (TDEE):
' + Math.round(tdee) + ' calories/day' +
'Based on your goal to
' + goal + ' weight, your estimated daily calorie intake should be around: ' +
'
' + Math.round(targetCalories) + ' calories/day ' + goalDescription + " +
'
Note: These are estimates. Individual needs may vary based on metabolism, body composition, and other factors. Consult a healthcare professional or registered dietitian for personalized advice.';
}
Understanding Your Calorie Needs
A calorie calculator is a tool designed to estimate the number of calories your body needs daily to maintain, lose, or gain weight. This estimation is based on several key factors that influence your metabolism and energy expenditure.
Basal Metabolic Rate (BMR)
Your Basal Metabolic Rate (BMR) is the number of calories your body burns at rest to perform basic life-sustaining functions like breathing, circulation, cell production, and nutrient processing. It's the minimum amount of energy required to keep your body functioning if you were to do nothing but rest for 24 hours. Our calculator uses the Mifflin-St Jeor equation, which is widely recognized for its accuracy:
- 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)
While BMR accounts for your resting energy, your Total Daily Energy Expenditure (TDEE) includes the calories you burn through physical activity. This is calculated by multiplying your BMR by an activity factor:
- Sedentary: BMR × 1.2 (little or no exercise)
- Lightly Active: BMR × 1.375 (light exercise/sports 1-3 days/week)
- Moderately Active: BMR × 1.55 (moderate exercise/sports 3-5 days/week)
- Very Active: BMR × 1.725 (hard exercise/sports 6-7 days a week)
- Extra Active: BMR × 1.9 (very hard exercise/physical job/training twice a day)
Your TDEE represents the total number of calories you burn in a day, including your BMR and all physical activity.
Factors Influencing Calorie Needs
- Age: Metabolism tends to slow down with age, reducing calorie needs.
- Gender: Men generally have higher muscle mass and lower body fat percentage than women, leading to a higher BMR.
- Weight: Heavier individuals require more energy to maintain their body functions.
- Height: Taller individuals typically have a larger surface area and more lean mass, requiring more calories.
- Activity Level: The more active you are, the more calories you burn.
- Body Composition: Muscle tissue burns more calories at rest than fat tissue.
Weight Management Goals
Once your TDEE is established, you can adjust your calorie intake based on your weight goals:
- Maintain Weight: Consume calories equal to your TDEE.
- Lose Weight: Create a calorie deficit, typically by consuming 500 calories less than your TDEE per day to lose approximately 1 pound (0.45 kg) per week.
- Gain Weight: Create a calorie surplus, typically by consuming 500 calories more than your TDEE per day to gain approximately 1 pound (0.45 kg) per week.
Example Calculation
Let's consider a 30-year-old male, weighing 70 kg (154 lbs), 175 cm (5'9″) tall, with a moderately active lifestyle, aiming to maintain weight.
- BMR Calculation: (10 × 70) + (6.25 × 175) – (5 × 30) + 5 = 700 + 1093.75 – 150 + 5 = 1648.75 calories.
- TDEE Calculation: 1648.75 (BMR) × 1.55 (Moderately Active) = 2555.56 calories.
- Goal Adjustment: To maintain weight, he would aim for approximately 2556 calories per day.
If this same individual wanted to lose weight, he would aim for approximately 2556 – 500 = 2056 calories per day.
Remember, these calculations provide a good starting point, but individual results may vary. It's always best to listen to your body and consult with a health professional for personalized guidance.