Basal Rate Calculator

by

Basal Metabolic Rate (BMR) Calculator

Calculate your Basal Metabolic Rate (BMR), the number of calories your body needs to perform basic, life-sustaining functions at rest.

function calculateBMR() { var weight = parseFloat(document.getElementById("weight").value); var height = parseFloat(document.getElementById("height").value); var age = parseFloat(document.getElementById("age").value); var sex = document.querySelector('input[name="sex"]:checked').value; var bmr = 0; 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; } if (sex === "male") { // Mifflin-St Jeor Equation for Men bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5; } else { // Mifflin-St Jeor Equation for Women bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161; } document.getElementById("result").innerHTML = "
" + "Your Basal Metabolic Rate (BMR) is:" + "

" + bmr.toFixed(2) + " calories/day

" + "This is the estimated number of calories your body burns at rest to maintain vital functions." + "
"; } .calculator-container { font-family: sans-serif; max-width: 600px; margin: 20px auto; padding: 20px; border: 1px solid #ccc; border-radius: 8px; box-shadow: 0 2px 4px rgba(0,0,0,0.1); background-color: #f9f9f9; } .calculator-inputs h2 { text-align: center; color: #333; margin-bottom: 15px; } .calculator-inputs p { text-align: center; color: #555; margin-bottom: 25px; line-height: 1.6; } .input-group { margin-bottom: 15px; display: flex; align-items: center; } .input-group label { display: inline-block; width: 120px; margin-right: 10px; font-weight: bold; color: #444; } .input-group input[type="number"], .input-group input[type="text"] { flex-grow: 1; padding: 8px; border: 1px solid #ddd; border-radius: 4px; box-sizing: border-box; /* Ensure padding doesn't affect width */ } .radio-group { display: flex; align-items: center; gap: 15px; } .radio-group label { width: auto; font-weight: normal; color: #555; } .calculator-inputs button { display: block; width: 100%; padding: 10px 15px; background-color: #007bff; color: white; border: none; border-radius: 4px; font-size: 16px; cursor: pointer; transition: background-color 0.3s ease; margin-top: 20px; } .calculator-inputs button:hover { background-color: #0056b3; } .calculator-result { margin-top: 30px; padding: 20px; border: 1px solid #e0e0e0; border-radius: 8px; background-color: #ffffff; text-align: center; } .calculator-result h2 { color: #28a745; margin: 0; } .calculator-result p { color: #666; margin-top: 10px; line-height: 1.5; } .result-item { display: flex; flex-direction: column; align-items: center; }

Understanding Your Basal Metabolic Rate (BMR)

Your Basal Metabolic Rate (BMR) represents the minimum energy your body requires to maintain essential physiological functions when you are at rest, such as breathing, circulation, cell production, and nutrient processing. It's essentially the number of calories your body burns just to keep you alive and functioning, even if you were to lie in bed all day without moving.

Several factors influence your BMR, including:

  • Age: BMR generally decreases with age as muscle mass tends to decline.
  • Sex: Men typically have a higher BMR than women due to generally higher muscle mass and lower body fat percentage.
  • Body Composition: Muscle tissue burns more calories at rest than fat tissue. Individuals with more muscle mass will have a higher BMR.
  • Body Size and Shape: Taller and larger individuals usually have a higher BMR.
  • Genetics: Your inherited traits play a role in your metabolic rate.
  • Hormones: Thyroid hormones, in particular, significantly regulate metabolism.

Understanding your BMR is a crucial first step in managing your weight and overall health. It provides a baseline for estimating your total daily energy expenditure (TDEE), which accounts for your BMR plus the calories burned through physical activity and the thermic effect of food. By knowing your BMR, you can make more informed decisions about your caloric intake to achieve your health goals, whether it's weight loss, maintenance, or gain.

The calculator above uses the Mifflin-St Jeor equation, which is widely considered one of the most accurate formulas for estimating BMR. It requires your weight, height, age, and sex to provide a personalized estimate.

Example Calculation:

Let's consider Sarah, a 30-year-old woman who weighs 65 kg and is 165 cm tall.

  • Weight: 65 kg
  • Height: 165 cm
  • Age: 30 years
  • Sex: Female

Using the Mifflin-St Jeor equation for women: BMR = (10 * weight) + (6.25 * height) – (5 * age) – 161 BMR = (10 * 65) + (6.25 * 165) – (5 * 30) – 161 BMR = 650 + 1031.25 – 150 – 161 BMR = 1370.25 calories/day

Therefore, Sarah's estimated Basal Metabolic Rate is approximately 1370.25 calories per day. This means her body burns about 1370 calories at rest to sustain her basic life functions.

Leave a Comment