Base Metabolic Rate Calculator

Base Metabolic Rate (BMR) Calculator

Your Base Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions at rest. This includes breathing, circulation, cell production, and nutrient processing. It's the minimum energy your body requires to keep you alive if you were to do nothing all day. Factors like age, sex, weight, and height significantly influence your BMR.

Male Female

Your Estimated BMR:

— kcal/day

Understanding Your BMR

The BMR is a foundational component of your total daily energy expenditure. It represents the calories burned at complete rest. The remaining calories you burn throughout the day come from the Thermic Effect of Food (TEF) and physical activity (exercise and non-exercise activity thermogenesis – NEAT).

Knowing your BMR can help you understand your basic caloric needs. For weight management, this is a crucial starting point. You can then adjust your caloric intake based on your activity level to either lose, maintain, or gain weight.

Formulas Used:

  • Mifflin-St Jeor Equation (generally considered more accurate):
    • 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

Example Calculation:

Let's consider a 30-year-old male who weighs 75 kg and is 180 cm tall.

Using the Mifflin-St Jeor equation for men:

BMR = (10 * 75) + (6.25 * 180) – (5 * 30) + 5

BMR = 750 + 1125 – 150 + 5

BMR = 1730 kcal/day

This means his body needs approximately 1730 calories per day just to maintain basic functions while at rest.

function calculateBMR() { var weight = document.getElementById("weight").value; var height = document.getElementById("height").value; var age = document.getElementById("age").value; var gender = document.getElementById("gender").value; var resultElement = document.getElementById("result"); var bmr = 0; // Validate inputs if (isNaN(weight) || weight <= 0) { resultElement.innerHTML = "Please enter a valid weight."; return; } if (isNaN(height) || height <= 0) { resultElement.innerHTML = "Please enter a valid height."; return; } if (isNaN(age) || age <= 0) { resultElement.innerHTML = "Please enter a valid age."; return; } if (gender === "male") { bmr = (10 * parseFloat(weight)) + (6.25 * parseFloat(height)) – (5 * parseFloat(age)) + 5; } else { // female bmr = (10 * parseFloat(weight)) + (6.25 * parseFloat(height)) – (5 * parseFloat(age)) – 161; } resultElement.innerHTML = Math.round(bmr) + " kcal/day"; } .bmr-calculator { font-family: sans-serif; border: 1px solid #eee; padding: 20px; border-radius: 8px; max-width: 600px; margin: 20px auto; background-color: #f9f9f9; } .bmr-calculator h2, .bmr-calculator h3, .bmr-calculator h4 { color: #333; margin-bottom: 15px; } .bmr-calculator p { color: #555; line-height: 1.6; margin-bottom: 15px; } .input-section { margin-bottom: 15px; } .input-section label { display: block; margin-bottom: 5px; font-weight: bold; color: #444; } .input-section input[type="number"], .input-section select { width: calc(100% – 12px); padding: 10px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; /* Include padding and border in the element's total width and height */ } .bmr-calculator button { background-color: #4CAF50; color: white; padding: 12px 20px; border: none; border-radius: 4px; cursor: pointer; font-size: 16px; margin-top: 10px; margin-bottom: 20px; transition: background-color 0.3s ease; } .bmr-calculator button:hover { background-color: #45a049; } .result-section { margin-top: 20px; padding: 15px; background-color: #e9f7ef; border-left: 5px solid #4CAF50; border-radius: 4px; } .result-section h3 { margin-top: 0; color: #333; } #result { font-size: 24px; font-weight: bold; color: #4CAF50; } .explanation { margin-top: 30px; padding-top: 20px; border-top: 1px solid #eee; } .explanation ul { margin-left: 20px; line-height: 1.6; } .explanation li { margin-bottom: 8px; } .explanation ul ul { margin-top: 5px; margin-bottom: 5px; }

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