Daily Metabolic Rate Calculator

by

Daily 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)
function calculateMetabolicRate() { var weight = parseFloat(document.getElementById("weight").value); var height = parseFloat(document.getElementById("height").value); var age = parseInt(document.getElementById("age").value); var gender = document.getElementById("gender").value; var activityLevel = document.getElementById("activityLevel").value; var bmr = 0; var tdee = 0; if (isNaN(weight) || isNaN(height) || isNaN(age) || weight <= 0 || height <= 0 || age <= 0) { document.getElementById("result").innerHTML = "Please enter valid positive numbers for weight, height, and age."; 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) var activityMultiplier = 0; switch (activityLevel) { case "sedentary": activityMultiplier = 1.2; break; case "lightlyActive": activityMultiplier = 1.375; break; case "moderatelyActive": activityMultiplier = 1.55; break; case "veryActive": activityMultiplier = 1.725; break; case "extraActive": activityMultiplier = 1.9; break; } tdee = bmr * activityMultiplier; document.getElementById("result").innerHTML = "Your Basal Metabolic Rate (BMR): " + bmr.toFixed(2) + " kcal/day" + "Your Total Daily Energy Expenditure (TDEE): " + tdee.toFixed(2) + " kcal/day"; }

Understanding Your Daily Metabolic Rate

Your daily metabolic rate is a crucial factor in understanding your body's energy needs. It's essentially the total number of calories your body burns in a 24-hour period to maintain basic life functions and support your physical activities. This rate is composed of two main components: your Basal Metabolic Rate (BMR) and your Total Daily Energy Expenditure (TDEE).

Basal Metabolic Rate (BMR)

BMR represents the minimum amount of energy (calories) your body needs to function at rest. This includes vital processes like breathing, circulating blood, maintaining body temperature, cell production, and brain activity. It's the energy your body would use if you were to sleep for 24 hours straight. BMR is influenced by several factors, including your weight, height, age, and gender. Generally, individuals with more muscle mass have a higher BMR because muscle tissue burns more calories than fat tissue, even at rest.

The Mifflin-St Jeor equation is a widely used and scientifically validated formula to estimate BMR:

  • 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)

TDEE takes your BMR a step further by accounting for the calories you burn through all your daily activities, from exercise to simply walking around. It's a more comprehensive picture of your total daily calorie needs. Your TDEE is calculated by multiplying your BMR by an "activity factor" that corresponds to your lifestyle.

The activity factors are generally:

  • Sedentary: Little to no exercise. Activity multiplier ≈ 1.2
  • Lightly Active: Light exercise or sports 1-3 days a week. Activity multiplier ≈ 1.375
  • Moderately Active: Moderate exercise or sports 3-5 days a week. Activity multiplier ≈ 1.55
  • Very Active: Hard exercise or sports 6-7 days a week. Activity multiplier ≈ 1.725
  • Extra Active: Very hard exercise or sports and a physical job. Activity multiplier ≈ 1.9

Understanding your TDEE can be invaluable for weight management. If your calorie intake consistently matches your TDEE, your weight will likely remain stable. Consuming fewer calories than your TDEE will generally lead to weight loss, while consuming more will lead to weight gain.

How to Use This Calculator

To get an estimate of your metabolic rate, simply input your current weight in kilograms, height in centimeters, age in years, select your gender, and choose the activity level that best describes your lifestyle. The calculator will then provide you with your estimated BMR and TDEE in kilocalories (kcal) per day.

Example Calculation:

Let's consider a 30-year-old male who weighs 80 kg, is 180 cm tall, and leads a moderately active lifestyle (exercises 3-5 days a week).

  • Weight: 80 kg
  • Height: 180 cm
  • Age: 30 years
  • Gender: Male
  • Activity Level: Moderately Active (multiplier 1.55)

First, calculate BMR:

BMR = (10 × 80) + (6.25 × 180) – (5 × 30) + 5

BMR = 800 + 1125 – 150 + 5

BMR = 1780 kcal/day

Next, calculate TDEE:

TDEE = BMR × Activity Multiplier

TDEE = 1780 × 1.55

TDEE = 2759 kcal/day

This individual would need approximately 1780 kcal per day to maintain basic bodily functions and around 2759 kcal per day to maintain his current weight, considering his activity level.

Leave a Comment