.calorie-deficit-calculator-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 700px;
margin: 20px auto;
padding: 25px;
border-radius: 12px;
background-color: #f9f9f9;
box-shadow: 0 6px 15px rgba(0, 0, 0, 0.1);
border: 1px solid #e0e0e0;
}
.calorie-deficit-calculator-container h2 {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
font-size: 1.8em;
border-bottom: 2px solid #3498db;
padding-bottom: 10px;
}
.calorie-deficit-calculator-container .input-group {
margin-bottom: 18px;
display: flex;
flex-direction: column;
}
.calorie-deficit-calculator-container label {
margin-bottom: 8px;
color: #34495e;
font-weight: bold;
font-size: 0.95em;
}
.calorie-deficit-calculator-container input[type="number"],
.calorie-deficit-calculator-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;
}
.calorie-deficit-calculator-container input[type="number"]:focus,
.calorie-deficit-calculator-container select:focus {
border-color: #3498db;
outline: none;
box-shadow: 0 0 5px rgba(52, 152, 219, 0.4);
}
.calorie-deficit-calculator-container .radio-group {
display: flex;
gap: 20px;
margin-top: 5px;
}
.calorie-deficit-calculator-container .radio-group label {
font-weight: normal;
display: flex;
align-items: center;
cursor: pointer;
}
.calorie-deficit-calculator-container .radio-group input[type="radio"] {
margin-right: 8px;
transform: scale(1.2);
}
.calorie-deficit-calculator-container button {
width: 100%;
padding: 14px;
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;
}
.calorie-deficit-calculator-container button:hover {
background-color: #218838;
transform: translateY(-2px);
}
.calorie-deficit-calculator-container #calorieResult {
margin-top: 30px;
padding: 20px;
background-color: #e8f5e9;
border: 1px solid #c8e6c9;
border-radius: 8px;
text-align: center;
font-size: 1.15em;
color: #2c3e50;
line-height: 1.6;
}
.calorie-deficit-calculator-container #calorieResult strong {
color: #28a745;
font-size: 1.3em;
}
.calorie-deficit-calculator-container .error-message {
color: #dc3545;
font-size: 0.9em;
margin-top: -10px;
margin-bottom: 10px;
display: none; /* Hidden by default */
}
function calculateCalorieDeficit() {
// Clear previous errors
document.getElementById('errorCurrentWeight').style.display = 'none';
document.getElementById('errorHeight').style.display = 'none';
document.getElementById('errorAge').style.display = 'none';
document.getElementById('calorieResult').innerHTML = ";
// Get input values
var currentWeightLbs = parseFloat(document.getElementById('currentWeight').value);
var heightFeet = parseFloat(document.getElementById('heightFeet').value);
var heightInches = parseFloat(document.getElementById('heightInches').value);
var age = parseFloat(document.getElementById('age').value);
var gender = document.querySelector('input[name="gender"]:checked').value;
var activityFactor = parseFloat(document.getElementById('activityLevel').value);
var weightLossLbsPerWeek = parseFloat(document.getElementById('weightLossGoal').value);
// Input validation
var isValid = true;
if (isNaN(currentWeightLbs) || currentWeightLbs <= 0) {
document.getElementById('errorCurrentWeight').style.display = 'block';
isValid = false;
}
if (isNaN(heightFeet) || heightFeet <= 0 || isNaN(heightInches) || heightInches 11) {
document.getElementById('errorHeight').style.display = 'block';
isValid = false;
}
if (isNaN(age) || age <= 0) {
document.getElementById('errorAge').style.display = 'block';
isValid = false;
}
if (!isValid) {
document.getElementById('calorieResult').innerHTML = 'Please correct the errors in the input fields.';
return;
}
// Convert units
var currentWeightKg = currentWeightLbs * 0.453592;
var totalHeightInches = (heightFeet * 12) + heightInches;
var totalHeightCm = totalHeightInches * 2.54;
// Calculate Basal Metabolic Rate (BMR) using Mifflin-St Jeor Equation
var bmr;
if (gender === 'male') {
bmr = (10 * currentWeightKg) + (6.25 * totalHeightCm) – (5 * age) + 5;
} else { // female
bmr = (10 * currentWeightKg) + (6.25 * totalHeightCm) – (5 * age) – 161;
}
// Calculate Total Daily Energy Expenditure (TDEE)
var tdee = bmr * activityFactor;
// Calculate calorie deficit for desired weight loss
// 1 lb of fat is approximately 3500 calories
// Daily deficit = (lbs per week * 3500) / 7
var dailyCalorieDeficit = (weightLossLbsPerWeek * 3500) / 7;
// Calculate target daily calorie intake
var targetDailyCalories = tdee – dailyCalorieDeficit;
// Ensure target calories are not too low (e.g., below 1200 for women, 1500 for men)
var minCalories = (gender === 'male') ? 1500 : 1200;
if (targetDailyCalories < minCalories) {
targetDailyCalories = minCalories;
document.getElementById('calorieResult').innerHTML =
'Your calculated target daily calories for a ' + weightLossLbsPerWeek + ' lb/week loss is ' + Math.round(tdee – dailyCalorieDeficit) + ' calories.' +
'Warning: This value is below the recommended minimum of ' + minCalories + ' calories per day for safe weight loss. We recommend adjusting your weight loss goal or consulting a professional.' +
'For safe weight loss, aim for at least ' + minCalories + ' calories per day.' +
'Your estimated Basal Metabolic Rate (BMR): ' + Math.round(bmr) + ' calories' +
'Your estimated Total Daily Energy Expenditure (TDEE): ' + Math.round(tdee) + ' calories';
} else {
document.getElementById('calorieResult').innerHTML =
'To lose ' + weightLossLbsPerWeek + ' lbs per week, your estimated daily calorie target is: ' + Math.round(targetDailyCalories) + ' calories.' +
'Your estimated Basal Metabolic Rate (BMR): ' + Math.round(bmr) + ' calories' +
'Your estimated Total Daily Energy Expenditure (TDEE): ' + Math.round(tdee) + ' calories';
}
}
Daily Calorie Target for Weight Loss
Please enter a valid weight.
Please enter a valid height.
Please enter a valid age.
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)
0.5 lbs per week (250 calorie deficit)
1.0 lbs per week (500 calorie deficit)
1.5 lbs per week (750 calorie deficit)
2.0 lbs per week (1000 calorie deficit)
Understanding Your Calorie Target for Weight Loss
Achieving sustainable weight loss often boils down to creating a consistent calorie deficit. This means consuming fewer calories than your body burns each day. Our Daily Calorie Target for Weight Loss calculator helps you estimate the ideal number of calories you should aim for to reach your weight loss goals safely and effectively.
What is a Calorie Deficit?
A calorie deficit occurs when you consume fewer calories than your body expends. Your body needs a certain amount of energy (calories) to perform basic functions like breathing, circulating blood, and maintaining body temperature (Basal Metabolic Rate or BMR), plus additional energy for physical activity. When you consistently eat less than your Total Daily Energy Expenditure (TDEE), your body starts to use stored fat for energy, leading to weight loss.
How the Calculator Works
This calculator uses a multi-step approach to determine your personalized calorie target:
- Basal Metabolic Rate (BMR): First, it estimates your BMR using the Mifflin-St Jeor equation, which is widely recognized for its accuracy. BMR is the number of calories your body burns at rest to maintain vital functions. Factors like your age, gender, weight, and height influence your BMR.
- Total Daily Energy Expenditure (TDEE): Your BMR is then multiplied by an activity factor to calculate your TDEE. This accounts for the calories you burn through daily activities, exercise, and digestion. The more active you are, the higher your TDEE.
- Calorie Deficit: To lose weight, you need to create a deficit from your TDEE. A common guideline is that a deficit of 3500 calories equals approximately one pound of fat loss. Therefore, a daily deficit of 500 calories aims for about one pound of weight loss per week (500 calories/day * 7 days/week = 3500 calories/week).
- Target Daily Calories: Finally, the calculator subtracts your desired daily calorie deficit from your TDEE to provide your estimated daily calorie target for weight loss.
Realistic Weight Loss Goals
While it might be tempting to aim for rapid weight loss, a healthy and sustainable rate is generally considered to be 1 to 2 pounds per week. Losing weight too quickly can lead to muscle loss, nutritional deficiencies, and may be harder to maintain long-term. Our calculator allows you to select a realistic weekly weight loss goal, from 0.5 lbs to 2 lbs per week.
Important Considerations
- Minimum Calorie Intake: The calculator includes a safeguard to prevent recommending dangerously low calorie targets. Generally, women should not consume fewer than 1200 calories per day, and men no fewer than 1500 calories per day, without medical supervision.
- Individual Variation: These calculations are estimates. Individual metabolic rates can vary, and factors like genetics, hormones, and certain medical conditions can influence your actual calorie needs.
- Nutrient Density: Focus on consuming nutrient-dense foods (lean proteins, whole grains, fruits, vegetables) within your calorie target to ensure you're getting essential vitamins and minerals.
- Consult a Professional: For personalized advice, especially if you have underlying health conditions or significant weight loss goals, always consult with a doctor or a registered dietitian.
Example Calculation:
Let's consider a 35-year-old female who is 5 feet 6 inches tall, weighs 160 lbs, and has a moderately active lifestyle, aiming to lose 1 lb per week.
- Inputs:
- Current Weight: 160 lbs
- Height: 5'6″
- Age: 35 years
- Gender: Female
- Activity Level: Moderately Active (factor 1.55)
- Desired Weekly Weight Loss: 1 lb
- Conversions:
- Weight: 160 lbs * 0.453592 = 72.57 kg
- Height: (5*12 + 6) inches = 66 inches * 2.54 = 167.64 cm
- BMR (Mifflin-St Jeor for Female):
- BMR = (10 * 72.57) + (6.25 * 167.64) – (5 * 35) – 161
- BMR = 725.7 + 1047.75 – 175 – 161 = 1437.45 calories
- TDEE:
- TDEE = BMR * Activity Factor = 1437.45 * 1.55 = 2228.04 calories
- Daily Calorie Deficit:
- For 1 lb/week loss: (1 * 3500) / 7 = 500 calories/day
- Target Daily Calories:
- Target = TDEE – Daily Deficit = 2228.04 – 500 = 1728.04 calories
Based on these inputs, this individual would aim for approximately 1728 calories per day to lose 1 lb per week.