Calculator Cal

Basal Metabolic Rate (BMR) Calculator

Your Basal Metabolic Rate (BMR) will appear here.

function calculateBMR() { var genderMale = document.getElementById("genderMale").checked; var genderFemale = document.getElementById("genderFemale").checked; var ageYears = parseFloat(document.getElementById("ageYears").value); var weightKg = parseFloat(document.getElementById("weightKg").value); var heightCm = parseFloat(document.getElementById("heightCm").value); var bmrResultDiv = document.getElementById("bmrResult"); if (isNaN(ageYears) || ageYears <= 0 || isNaN(weightKg) || weightKg <= 0 || isNaN(heightCm) || heightCm <= 0) { bmrResultDiv.innerHTML = "Please enter valid positive numbers for all fields."; return; } var bmr; // Mifflin-St Jeor Equation if (genderMale) { bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * ageYears) + 5; } else if (genderFemale) { bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * ageYears) – 161; } else { bmrResultDiv.innerHTML = "Please select your gender."; return; } bmrResultDiv.innerHTML = "Your Basal Metabolic Rate (BMR) is: " + bmr.toFixed(2) + " calories/day."; }

Understanding Your Basal Metabolic Rate (BMR)

The Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic, life-sustaining functions while at rest. These essential functions include breathing, circulation, cell production, nutrient processing, and maintaining body temperature. Your BMR accounts for the largest portion of your total daily energy expenditure (TDEE), often between 60% to 75%.

Why is BMR Important?

Knowing your BMR can be a powerful tool for managing your weight and understanding your body's energy needs. If you're looking to lose weight, maintain weight, or gain weight, your BMR provides a baseline for how many calories your body burns without any additional activity. By understanding this baseline, you can then factor in your activity level to determine your total daily calorie needs.

• Weight Loss: To lose weight, you generally need to consume fewer calories than your body burns. Your BMR helps you establish a calorie deficit.
• Weight Maintenance: To maintain your current weight, you need to consume roughly the same number of calories your body burns, including your BMR and activity.
• Weight Gain: To gain weight, you need to consume more calories than your body burns.

How is BMR Calculated?

Our BMR calculator uses the Mifflin-St Jeor equation, which is widely considered one of the most accurate formulas for estimating BMR. This equation takes into account several key factors:

• Gender: Men generally have a higher BMR than women due to a higher muscle mass percentage.
• Age: BMR tends to decrease with age as muscle mass declines and metabolic processes slow down.
• Weight: Heavier individuals typically have a higher BMR because more energy is required to maintain a larger body mass.
• Height: Taller individuals often have a higher BMR as they tend to have a larger surface area and more lean body mass.

The formulas used are:

• 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 is 175 cm tall and weighs 70 kg:

BMR = (10 × 70) + (6.25 × 175) – (5 × 30) + 5

BMR = 700 + 1093.75 – 150 + 5

BMR = 1648.75 calories/day

Now, consider a 30-year-old female who is 160 cm tall and weighs 60 kg:

BMR = (10 × 60) + (6.25 × 160) – (5 × 30) – 161

BMR = 600 + 1000 – 150 – 161

BMR = 1289 calories/day

These examples demonstrate how different inputs lead to varying BMR values, reflecting individual metabolic needs.

What to Do with Your BMR Result?

Your BMR is just the starting point. To get a more complete picture of your daily calorie needs, you'll need to multiply your BMR by an activity factor. This factor ranges from 1.2 for sedentary individuals to 1.9 for very active individuals. This will give you your Total Daily Energy Expenditure (TDEE), which is the total number of calories your body burns in a day, including exercise and daily activities.

Use this calculator to get your baseline BMR, and then consider your lifestyle to determine your overall calorie requirements for your health and fitness goals.