Base Metabolic Rate Calculator Uk

Understanding Your Basal Metabolic Rate (BMR)

Your Basal Metabolic Rate (BMR) is the minimum number of calories your body needs to function at rest. This includes basic life-sustaining activities like breathing, circulating blood, and cell production. It's essentially the energy your body burns just to keep itself alive, even if you were to do nothing all day.

Knowing your BMR can be a valuable tool for understanding your overall caloric needs. When combined with your activity level, it helps form the basis for estimating your Total Daily Energy Expenditure (TDEE), which is crucial for weight management, whether you're looking to lose, gain, or maintain weight.

Several formulas exist to estimate BMR, with the most commonly used being the Harris-Benedict equation and the Mifflin-St Jeor equation. The Mifflin-St Jeor equation is generally considered more accurate for most people.

Factors Affecting BMR:

  • Age: BMR typically decreases with age.
  • Sex: Men generally have a higher BMR than women due to greater muscle mass.
  • Body Composition: Muscle tissue burns more calories than fat tissue, so a higher muscle mass leads to a higher BMR.
  • Weight and Height: These are key components in BMR calculations.
  • Genetics: Individual genetic makeup can play a role.
  • Hormones: Thyroid hormones, for example, significantly impact metabolism.

This calculator uses the Mifflin-St Jeor equation to provide an estimate of your BMR. Remember that this is an estimation, and individual metabolic rates can vary.

BMR Calculator (Mifflin-St Jeor Equation)

Male Female
function calculateBMR() { var gender = document.getElementById("gender").value; var weight = document.getElementById("weight").value; var heightCm = document.getElementById("heightCm").value; var age = document.getElementById("age").value; var weightKg = parseFloat(weight); var heightCmValue = parseFloat(heightCm); var ageValue = parseInt(age); var bmr = 0; if (isNaN(weightKg) || isNaN(heightCmValue) || isNaN(ageValue) || weightKg <= 0 || heightCmValue <= 0 || ageValue <= 0) { document.getElementById("bmrResult").innerHTML = "Please enter valid positive numbers for all fields."; return; } if (gender === "male") { // Mifflin-St Jeor Equation for Men: // BMR = (10 * weight in kg) + (6.25 * height in cm) – (5 * age in years) + 5 bmr = (10 * weightKg) + (6.25 * heightCmValue) – (5 * ageValue) + 5; } else { // female // Mifflin-St Jeor Equation for Women: // BMR = (10 * weight in kg) + (6.25 * height in cm) – (5 * age in years) – 161 bmr = (10 * weightKg) + (6.25 * heightCmValue) – (5 * ageValue) – 161; } // Ensure BMR is not negative (though unlikely with positive inputs) if (bmr < 0) { bmr = 0; } document.getElementById("bmrResult").innerHTML = "Your estimated Basal Metabolic Rate (BMR) is: " + bmr.toFixed(2) + " kcal/day"; } .bmr-calculator-wrapper { font-family: sans-serif; line-height: 1.6; max-width: 900px; margin: 20px auto; padding: 20px; border: 1px solid #e0e0e0; border-radius: 8px; background-color: #f9f9f9; display: flex; flex-wrap: wrap; gap: 30px; } .bmr-calculator-wrapper .article-content { flex: 1; min-width: 300px; } .bmr-calculator-wrapper .article-content h2, .bmr-calculator-wrapper .article-content h3 { color: #333; margin-bottom: 15px; } .bmr-calculator-wrapper .article-content ul { margin-left: 20px; margin-bottom: 15px; } .bmr-calculator-wrapper .article-content li { margin-bottom: 8px; } .bmr-calculator-wrapper .calculator-ui { flex: 1; min-width: 300px; background-color: #ffffff; padding: 25px; border-radius: 8px; box-shadow: 0 2px 5px rgba(0,0,0,0.1); } .bmr-calculator-wrapper .calculator-ui h3 { margin-top: 0; text-align: center; color: #555; margin-bottom: 20px; } .bmr-calculator-wrapper .form-group { margin-bottom: 15px; } .bmr-calculator-wrapper label { display: block; margin-bottom: 8px; font-weight: bold; color: #555; } .bmr-calculator-wrapper input[type="number"], .bmr-calculator-wrapper select { width: calc(100% – 22px); padding: 10px; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box; font-size: 1rem; } .bmr-calculator-wrapper button { width: 100%; padding: 12px 20px; background-color: #4CAF50; color: white; border: none; border-radius: 4px; cursor: pointer; font-size: 1.1rem; transition: background-color 0.3s ease; } .bmr-calculator-wrapper button:hover { background-color: #45a049; } .bmr-calculator-wrapper .result-display { margin-top: 20px; padding: 15px; background-color: #e7f3fe; border: 1px solid #b3d7f2; border-radius: 4px; text-align: center; font-size: 1.1rem; color: #333; } .bmr-calculator-wrapper .result-display strong { color: #4CAF50; }

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