.calories-calculator-lose-weight-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: #ffffff;
box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
color: #333;
}
.calories-calculator-lose-weight-container h2 {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
font-size: 1.8em;
}
.calories-calculator-lose-weight-container .input-group {
margin-bottom: 18px;
display: flex;
flex-direction: column;
}
.calories-calculator-lose-weight-container label {
margin-bottom: 8px;
font-weight: bold;
color: #555;
font-size: 0.95em;
}
.calories-calculator-lose-weight-container input[type="number"],
.calories-calculator-lose-weight-container select {
width: calc(100% – 20px);
padding: 12px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 1em;
box-sizing: border-box;
transition: border-color 0.3s ease;
}
.calories-calculator-lose-weight-container input[type="number"]:focus,
.calories-calculator-lose-weight-container select:focus {
border-color: #007bff;
outline: none;
box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.25);
}
.calories-calculator-lose-weight-container .radio-group {
display: flex;
gap: 20px;
margin-top: 5px;
}
.calories-calculator-lose-weight-container .radio-group label {
font-weight: normal;
display: flex;
align-items: center;
cursor: pointer;
}
.calories-calculator-lose-weight-container .radio-group input[type="radio"] {
margin-right: 8px;
transform: scale(1.2);
}
.calories-calculator-lose-weight-container button {
width: 100%;
padding: 14px 20px;
background-color: #28a745;
color: white;
border: none;
border-radius: 6px;
font-size: 1.1em;
font-weight: bold;
cursor: pointer;
transition: background-color 0.3s ease, transform 0.2s ease;
margin-top: 20px;
}
.calories-calculator-lose-weight-container button:hover {
background-color: #218838;
transform: translateY(-2px);
}
.calories-calculator-lose-weight-container .result-section {
margin-top: 30px;
padding: 20px;
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
text-align: center;
font-size: 1.1em;
color: #333;
}
.calories-calculator-lose-weight-container .result-section h3 {
color: #007bff;
margin-bottom: 15px;
font-size: 1.5em;
}
.calories-calculator-lose-weight-container .result-section p {
margin-bottom: 10px;
line-height: 1.6;
}
.calories-calculator-lose-weight-container .result-section strong {
color: #28a745;
font-size: 1.2em;
}
.calories-calculator-lose-weight-container .error-message {
color: #dc3545;
margin-top: 10px;
text-align: center;
font-weight: bold;
}
.calories-calculator-lose-weight-container .unit-toggle {
display: flex;
justify-content: flex-end;
margin-bottom: 10px;
gap: 10px;
}
.calories-calculator-lose-weight-container .unit-toggle button {
width: auto;
padding: 8px 15px;
font-size: 0.9em;
background-color: #6c757d;
border-radius: 5px;
transition: background-color 0.2s;
}
.calories-calculator-lose-weight-container .unit-toggle button.active {
background-color: #007bff;
}
.calories-calculator-lose-weight-container .unit-toggle button:hover {
background-color: #5a6268;
}
var currentWeightUnit = 'kg';
var currentHeightUnit = 'cm';
var currentLossUnit = 'kg';
function toggleWeightUnit(unit) {
currentWeightUnit = unit;
document.getElementById('weightUnitLabel').innerText = unit;
document.getElementById('weightUnitKg').classList.remove('active');
document.getElementById('weightUnitLbs').classList.remove('active');
document.getElementById('weightUnit' + unit.charAt(0).toUpperCase() + unit.slice(1)).classList.add('active');
}
function toggleHeightUnit(unit) {
currentHeightUnit = unit;
document.getElementById('heightUnitLabel').innerText = unit;
document.getElementById('heightUnitCm').classList.remove('active');
document.getElementById('heightUnitInches').classList.remove('active');
document.getElementById('heightUnit' + unit.charAt(0).toUpperCase() + unit.slice(1)).classList.add('active');
}
function toggleLossUnit(unit) {
currentLossUnit = unit;
document.getElementById('lossUnitLabel').innerText = unit;
document.getElementById('lossUnitKg').classList.remove('active');
document.getElementById('lossUnitLbs').classList.remove('active');
document.getElementById('lossUnit' + unit.charAt(0).toUpperCase() + unit.slice(1)).classList.add('active');
}
function calculateCalories() {
var age = parseFloat(document.getElementById('age').value);
var genderMale = document.getElementById('genderMale').checked;
var weightInput = parseFloat(document.getElementById('weightInput').value);
var heightInput = parseFloat(document.getElementById('heightInput').value);
var activityLevelMultiplier = parseFloat(document.getElementById('activityLevel').value);
var weightLossGoalInput = parseFloat(document.getElementById('weightLossGoalInput').value);
var errorMessageDiv = document.getElementById('errorMessage');
var resultDiv = document.getElementById('result');
errorMessageDiv.style.display = 'none';
resultDiv.style.display = 'none';
if (isNaN(age) || age <= 0 ||
isNaN(weightInput) || weightInput <= 0 ||
isNaN(heightInput) || heightInput <= 0 ||
isNaN(activityLevelMultiplier) ||
isNaN(weightLossGoalInput) || weightLossGoalInput <= 0) {
errorMessageDiv.innerText = 'Please enter valid positive numbers for all fields.';
errorMessageDiv.style.display = 'block';
return;
}
var weightKg = weightInput;
if (currentWeightUnit === 'lbs') {
weightKg = weightInput * 0.453592; // Convert lbs to kg
}
var heightCm = heightInput;
if (currentHeightUnit === 'inches') {
heightCm = heightInput * 2.54; // Convert inches to cm
}
var bmr;
if (genderMale) {
// Mifflin-St Jeor Equation for Men
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) + 5;
} else {
// Mifflin-St Jeor Equation for Women
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) – 161;
}
var tdee = bmr * activityLevelMultiplier;
var weightLossGoalKgPerWeek = weightLossGoalInput;
if (currentLossUnit === 'lbs') {
weightLossGoalKgPerWeek = weightLossGoalInput * 0.453592; // Convert lbs to kg
}
// 1 kg of fat is approximately 7700 calories
var dailyCalorieDeficit = (weightLossGoalKgPerWeek * 7700) / 7;
var recommendedCalories = tdee – dailyCalorieDeficit;
// Ensure recommended calories don't go too low for health
if (recommendedCalories < 1200 && !genderMale) { // Minimum for women
recommendedCalories = 1200;
errorMessageDiv.innerText = 'Warning: Recommended calories are very low. For health reasons, we suggest a minimum of 1200 calories/day for women. Please consult a professional.';
errorMessageDiv.style.display = 'block';
} else if (recommendedCalories < 1500 && genderMale) { // Minimum for men
recommendedCalories = 1500;
errorMessageDiv.innerText = 'Warning: Recommended calories are very low. For health reasons, we suggest a minimum of 1500 calories/day for men. Please consult a professional.';
errorMessageDiv.style.display = 'block';
}
document.getElementById('bmrResult').innerText = Math.round(bmr);
document.getElementById('tdeeResult').innerText = Math.round(tdee);
document.getElementById('recommendedCaloriesResult').innerText = Math.round(recommendedCalories);
resultDiv.style.display = 'block';
}
Weight Loss Calorie Calculator
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 a week)
Extremely Active (very hard exercise/physical job)
Your Calorie Recommendations
Your Basal Metabolic Rate (BMR): calories/day
Your Total Daily Energy Expenditure (TDEE): calories/day
To achieve your weight loss goal, aim for a daily intake of approximately: calories/day
Understanding Your Calorie Needs for Weight Loss
Losing weight effectively often comes down to creating a calorie deficit – consuming fewer calories than your body burns. This calculator helps you estimate your daily calorie needs and suggests a target for weight loss.
What is Basal Metabolic Rate (BMR)?
Your Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic, life-sustaining functions while at rest. This includes breathing, circulation, cell production, nutrient processing, and maintaining body temperature. It's the minimum energy required to keep you alive.
What is Total Daily Energy Expenditure (TDEE)?
Your Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a 24-hour period, including your BMR and the calories burned during physical activity. It accounts for everything from sleeping and eating to exercising and working. Your activity level significantly impacts your TDEE.
How the Calculator Works
This calculator uses the Mifflin-St Jeor equation, widely considered one of the most accurate formulas for estimating BMR. It takes into account your age, gender, weight, and height. Your BMR is then multiplied by an activity factor to determine your TDEE. Finally, to achieve your desired weight loss, a calorie deficit is applied to your TDEE.
- Mifflin-St Jeor Equation:
- 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
- Activity Multipliers:
- Sedentary (little or no exercise): BMR × 1.2
- Lightly Active (light exercise/sports 1-3 days/week): BMR × 1.375
- Moderately Active (moderate exercise/sports 3-5 days/week): BMR × 1.55
- Very Active (hard exercise/sports 6-7 days a week): BMR × 1.725
- Extremely Active (very hard exercise/physical job): BMR × 1.9
Healthy Weight Loss Goals
A safe and sustainable rate of weight loss is generally considered to be 0.5 to 1 kg (1 to 2 pounds) per week. To lose 1 kg of fat, you need to create a deficit of approximately 7700 calories. This calculator helps you determine the daily calorie deficit needed to meet your weekly weight loss goal.
Remember, these are estimates. Individual results can vary based on metabolism, body composition, genetics, and other factors. Always consult with a healthcare professional or a registered dietitian before making significant changes to your diet or exercise routine.