Basal Metabolic Rate Calculation Formula

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Basal Metabolic Rate (BMR) Calculator

Male Female

Your Basal Metabolic Rate (BMR):

BMR represents the number of calories your body needs to perform basic life-sustaining functions at rest. It does not include the calories burned through physical activity.

function calculateBMR() { var gender = document.getElementById("gender").value; var weight = parseFloat(document.getElementById("weight").value); var height = parseFloat(document.getElementById("height").value); var age = parseFloat(document.getElementById("age").value); var bmr = 0; // Validate inputs if (isNaN(weight) || isNaN(height) || isNaN(age) || weight <= 0 || height <= 0 || age <= 0) { document.getElementById("result").innerHTML = "Please enter valid positive numbers for all fields."; return; } // Harris-Benedict Equation (Revised) if (gender === "male") { bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5; } else { // female bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161; } // Display the result document.getElementById("result").innerHTML = bmr.toFixed(2) + " calories per day"; } .calculator-container { font-family: sans-serif; border: 1px solid #ccc; padding: 20px; border-radius: 8px; max-width: 500px; margin: 20px auto; box-shadow: 0 2px 5px rgba(0,0,0,0.1); } .input-section, .result-section { margin-bottom: 20px; } .input-section label { display: block; margin-bottom: 5px; font-weight: bold; } .input-section input[type="number"], .input-section select { width: calc(100% – 12px); padding: 8px; margin-bottom: 15px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; } .input-section button { background-color: #4CAF50; color: white; padding: 10px 15px; border: none; border-radius: 4px; cursor: pointer; font-size: 16px; width: 100%; } .input-section button:hover { background-color: #45a049; } .result-section h2 { margin-top: 0; color: #333; } #result { font-size: 24px; font-weight: bold; color: #d9534f; margin-top: 10px; } .result-section p { font-size: 14px; color: #555; line-height: 1.6; }

Understanding Basal Metabolic Rate (BMR)

Basal Metabolic Rate (BMR) is the minimum number of calories your body needs to function while at rest. This includes essential bodily processes such as breathing, blood circulation, cell production, nutrient processing, protein synthesis, and the function of your brain and nerves. It is essentially the energy expended for vital functions in a neutral environment and at a temperature that requires no extra heat production or cooling by the body.

Think of BMR as the energy your body would burn if you were to sleep for 24 hours straight. It's a fundamental aspect of understanding your body's energy requirements and is a crucial component in many weight management and fitness plans. Knowing your BMR helps in estimating your Total Daily Energy Expenditure (TDEE), which is your BMR plus the calories you burn through physical activity and the thermic effect of food.

Factors Influencing BMR:

  • Age: BMR generally decreases with age, as metabolic rate slows down.
  • Gender: Men typically have a higher BMR than women due to greater muscle mass.
  • Body Composition: Muscle tissue burns more calories at rest than fat tissue. Therefore, individuals with more muscle mass have a higher BMR.
  • Body Size and Shape: Larger individuals generally have a higher BMR.
  • Hormones: Thyroid hormones, for example, significantly impact metabolic rate.
  • Genetics: Individual genetic makeup plays a role in determining BMR.

How the BMR Calculator Works

The calculator above uses the Revised Harris-Benedict Equation, which is a widely accepted formula for estimating BMR. It takes into account your gender, weight, height, and age to provide an estimate of your basal metabolic rate in calories per day. It's important to note that this is an estimation, and individual BMR can vary.

Example Calculation:

Let's consider a 35-year-old male who weighs 80 kg and is 180 cm tall.

  • Gender: Male
  • Weight: 80 kg
  • Height: 180 cm
  • Age: 35 years

Using the formula for males:

BMR = (10 * Weight) + (6.25 * Height) – (5 * Age) + 5

BMR = (10 * 80) + (6.25 * 180) – (5 * 35) + 5

BMR = 800 + 1125 – 175 + 5

BMR = 1755 calories per day

So, this individual's estimated Basal Metabolic Rate is approximately 1755 calories per day.

Why is BMR Important?

Understanding your BMR is the first step in managing your caloric intake for weight loss, weight gain, or weight maintenance. By calculating your TDEE (which includes BMR and activity level), you can create a personalized nutrition plan that aligns with your goals.

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