How Do You Calculate Metabolic Rate

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Metabolic Rate Calculator

Male Female
Sedentary (little to 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/sports & physical job)
.metabolic-calculator { font-family: sans-serif; border: 1px solid #ccc; padding: 20px; border-radius: 8px; max-width: 500px; margin: 20px auto; background-color: #f9f9f9; } .metabolic-calculator h2 { text-align: center; margin-bottom: 20px; color: #333; } .calculator-inputs { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 15px; margin-bottom: 20px; } .input-group { display: flex; flex-direction: column; } .input-group label { margin-bottom: 5px; font-weight: bold; color: #555; } .input-group input, .input-group select { padding: 10px; border: 1px solid #ddd; border-radius: 4px; font-size: 1em; } .metabolic-calculator button { display: block; width: 100%; padding: 12px 20px; background-color: #007bff; color: white; border: none; border-radius: 4px; font-size: 1.1em; cursor: pointer; transition: background-color 0.3s ease; } .metabolic-calculator button:hover { background-color: #0056b3; } #result { margin-top: 25px; padding: 15px; border: 1px solid #e0e0e0; background-color: #fff; border-radius: 4px; font-size: 1.1em; text-align: center; color: #333; } #result strong { color: #007bff; } function calculateMetabolicRate() { var age = parseFloat(document.getElementById("age").value); var gender = document.getElementById("gender").value; var weight = parseFloat(document.getElementById("weight").value); var height = parseFloat(document.getElementById("height").value); var activityLevel = document.getElementById("activityLevel").value; var bmr = 0; // Basal Metabolic Rate var tef = 0; // Thermic Effect of Food var tdee = 0; // Total Daily Energy Expenditure // Input validation if (isNaN(age) || isNaN(weight) || isNaN(height) || age <= 0 || weight <= 0 || height <= 0) { document.getElementById("result").innerHTML = "Error: Please enter valid positive numbers for age, weight, and height."; return; } // Calculate Basal Metabolic Rate (BMR) using the 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; } // Calculate Total Daily Energy Expenditure (TDEE) by multiplying BMR by an activity factor var activityFactor; switch (activityLevel) { case "sedentary": activityFactor = 1.2; break; case "lightlyActive": activityFactor = 1.375; break; case "moderatelyActive": activityFactor = 1.55; break; case "veryActive": activityFactor = 1.725; break; case "extraActive": activityFactor = 1.9; break; default: activityFactor = 1.2; // Default to sedentary } tdee = bmr * activityFactor; // Thermic Effect of Food (TEF) is roughly 10% of TDEE tef = tdee * 0.10; var resultHTML = "

Your Estimated Metabolic Rate:

"; resultHTML += "Basal Metabolic Rate (BMR): " + bmr.toFixed(2) + " calories/day"; resultHTML += "Total Daily Energy Expenditure (TDEE): " + tdee.toFixed(2) + " calories/day"; resultHTML += "(This is the estimated total number of calories your body burns daily, including activity and digestion.)"; resultHTML += "Estimated Thermic Effect of Food (TEF): " + tef.toFixed(2) + " calories/day"; resultHTML += "(This is the energy used to digest, absorb, and metabolize food.)"; document.getElementById("result").innerHTML = resultHTML; }

Understanding Your Metabolic Rate

Your metabolic rate refers to the total number of calories your body burns to perform its basic functions and to sustain life. This includes everything from breathing and circulation to digestion and physical activity. Understanding your metabolic rate can be a crucial tool for managing your weight, improving your fitness, and optimizing your overall health.

Basal Metabolic Rate (BMR)

The Basal Metabolic Rate (BMR) is the minimum number of calories your body needs to function at rest. This is the energy required for vital bodily functions such as breathing, maintaining body temperature, and cell production. Factors like age, gender, weight, height, and body composition significantly influence BMR. Generally, the more muscle mass you have, the higher your BMR.

Total Daily Energy Expenditure (TDEE)

The Total Daily Energy Expenditure (TDEE) is a more comprehensive measure that includes your BMR plus the calories burned through all daily activities, including exercise and the thermic effect of food. It represents the total number of calories you burn in a 24-hour period. The TDEE calculator above estimates this by multiplying your BMR by an activity factor that reflects your lifestyle.

Activity Levels and Their Impact

  • Sedentary: Little to no exercise. Desk jobs and minimal physical activity.
  • Lightly Active: Light exercise or sports 1-3 days per week.
  • Moderately Active: Moderate exercise or sports 3-5 days per week.
  • Very Active: Hard exercise or sports 6-7 days per week.
  • Extra Active: Very hard exercise or sports and a physical job or training twice a day.

The higher your activity level, the more calories you will burn each day, leading to a higher TDEE.

Thermic Effect of Food (TEF)

The Thermic Effect of Food (TEF) is the energy your body expends to digest, absorb, and metabolize the food you eat. This process requires calories, and the amount varies depending on the macronutrient composition of your diet. Protein generally has the highest TEF, followed by carbohydrates, and then fats.

How to Use This Calculator

Enter your age, gender, weight in kilograms, height in centimeters, and select your general activity level. The calculator will then provide an estimate of your BMR and TDEE, helping you understand your daily caloric needs. This information can be a valuable starting point for creating a balanced diet and exercise plan tailored to your fitness goals, whether they are weight loss, weight gain, or maintenance.

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