Nutrition Calculator

Daily Calorie Needs Calculator

Estimate your daily calorie requirements based on your personal metrics, activity level, and weight management goals. This calculator uses the Mifflin-St Jeor equation for Basal Metabolic Rate (BMR) and applies activity factors to determine your Total Daily Energy Expenditure (TDEE).

function calculateNutrition() { var genderMale = document.getElementById('genderMale').checked; var age = parseFloat(document.getElementById('age').value); var weight = parseFloat(document.getElementById('weight').value); var height = parseFloat(document.getElementById('height').value); var activityFactor = parseFloat(document.getElementById('activityLevel').value); var goalAdjustment = parseFloat(document.getElementById('goal').value); var resultDiv = document.getElementById('nutritionResult'); resultDiv.innerHTML = "; // Clear previous results if (isNaN(age) || isNaN(weight) || isNaN(height) || age <= 0 || weight <= 0 || height <= 0) { resultDiv.innerHTML = 'Please enter valid positive numbers for Age, Weight, and Height.'; return; } var bmr; // Basal Metabolic Rate // Mifflin-St Jeor Equation if (genderMale) { bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5; } else { // Female bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161; } var tdee = bmr * activityFactor; // Total Daily Energy Expenditure var recommendedCalories = tdee + goalAdjustment; resultDiv.innerHTML = '

Your Estimated Daily Calorie Needs:

' + 'Basal Metabolic Rate (BMR): ' + bmr.toFixed(0) + ' calories/day' + 'Total Daily Energy Expenditure (TDEE): ' + tdee.toFixed(0) + ' calories/day' + 'Recommended Daily Calories for Goal: ' + recommendedCalories.toFixed(0) + ' calories/day' + 'These are estimates. Individual needs may vary. Consult a healthcare professional or registered dietitian for personalized advice.'; } .nutrition-calculator-container { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: #f9f9f9; border: 1px solid #ddd; border-radius: 8px; padding: 25px; max-width: 600px; margin: 20px auto; box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08); color: #333; } .nutrition-calculator-container h2 { text-align: center; color: #2c3e50; margin-bottom: 20px; font-size: 1.8em; } .nutrition-calculator-container p { font-size: 0.95em; line-height: 1.6; margin-bottom: 15px; } .calculator-form .form-group { margin-bottom: 18px; display: flex; flex-wrap: wrap; align-items: center; } .calculator-form label { flex: 1; min-width: 120px; margin-right: 15px; font-weight: bold; color: #555; font-size: 0.9em; } .calculator-form input[type="number"], .calculator-form select { flex: 2; padding: 10px 12px; border: 1px solid #ccc; border-radius: 5px; font-size: 1em; box-sizing: border-box; max-width: calc(100% – 140px); /* Adjust based on label width */ } .calculator-form input[type="radio"] { margin-right: 5px; margin-left: 15px; } .calculator-form input[type="radio"] + label { font-weight: normal; margin-right: 20px; min-width: unset; flex: unset; } .calculator-form small { font-size: 0.8em; color: #777; margin-left: 10px; flex-basis: 100%; text-align: right; margin-top: 5px; } .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; margin-top: 20px; } .calculator-form button:hover { background-color: #218838; } .calculator-result { margin-top: 30px; padding: 20px; background-color: #e9f7ef; border: 1px solid #d4edda; border-radius: 8px; text-align: center; } .calculator-result h3 { color: #2c3e50; margin-top: 0; font-size: 1.5em; } .calculator-result p { font-size: 1.1em; margin-bottom: 10px; color: #333; } .calculator-result .highlight { font-size: 1.3em; color: #007bff; font-weight: bold; } .calculator-result .error { color: #dc3545; font-weight: bold; } .calculator-result .note { font-size: 0.85em; color: #6c757d; margin-top: 15px; }

Understanding Your Daily Calorie Needs

Calculating your daily calorie needs is a fundamental step in managing your weight, whether you aim to lose, gain, or maintain it. This process involves understanding your Basal Metabolic Rate (BMR) and your Total Daily Energy Expenditure (TDEE).

What is 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. These include breathing, circulation, cell production, nutrient processing, and maintaining body temperature. Even when you're doing nothing, your body is constantly working, and BMR accounts for the energy required for these essential processes.

Several formulas exist to estimate BMR, with the Mifflin-St Jeor equation being one of the most widely accepted and accurate. It takes into account your gender, age, weight, and height:

• 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

As you can see, factors like higher weight and height generally lead to a higher BMR, while increasing age tends to decrease it.

What is Total Daily Energy Expenditure (TDEE)?

While BMR tells you how many calories you burn at rest, your Total Daily Energy Expenditure (TDEE) accounts for all the calories you burn throughout the day. This includes your BMR plus the energy expended through physical activity and the thermic effect of food (the energy used to digest, absorb, and metabolize food).

To calculate TDEE, your BMR is multiplied by an activity factor. This factor varies based on how active you are:

• 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

Your TDEE is a more accurate representation of the total calories you need to consume to maintain your current weight.

Adjusting for Weight Goals

Once you know your TDEE, you can adjust your calorie intake to achieve specific weight goals:

• Maintain Weight: Consume calories equal to your TDEE.
• Weight Loss: To lose weight, you need to create a calorie deficit, meaning you consume fewer calories than your TDEE. A deficit of 500 calories per day typically leads to a weight loss of approximately 0.5 kg (1 pound) per week.
• Weight Gain: To gain weight, you need to create a calorie surplus, consuming more calories than your TDEE. A surplus of 500 calories per day can lead to a weight gain of approximately 0.5 kg (1 pound) per week.

Our calculator provides common adjustments for mild, moderate, and extreme weight loss or gain, offering a starting point for your dietary planning.

Important Considerations

While this calculator provides a valuable estimate, it's important to remember that individual metabolic rates can vary. Factors like genetics, body composition (muscle vs. fat), hormonal balance, and certain medical conditions can influence your actual calorie needs. Always consider these calculations as a guideline.

For personalized nutrition advice and to ensure your diet is healthy and sustainable, it is highly recommended to consult with a healthcare professional or a registered dietitian.