Metabolic Rate Calculator Free

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Metabolic Rate Calculator

Calculate your BMR and Daily Calorie Needs

Male Female
Sedentary (Little or no exercise) Lightly Active (Exercise 1-3 days/week) Moderately Active (Exercise 3-5 days/week) Very Active (Exercise 6-7 days/week) Extra Active (Very hard exercise & physical job)

Your Results

BMR (Basal Metabolic Rate)
0
calories/day
TDEE (Total Daily Expenditure)
0
calories/day

Understanding Your Metabolic Rate

A metabolic rate calculator free tool is essential for anyone looking to manage their weight, gain muscle, or improve athletic performance. Your metabolism is the process by which your body converts what you eat and drink into energy.

BMR vs. TDEE: What is the Difference?

Our calculator provides two primary metrics:

  • Basal Metabolic Rate (BMR): This is the number of calories your body burns at rest to maintain vital functions like breathing, heart rate, and cell production. Imagine staying in bed all day; this is what you would burn.
  • Total Daily Energy Expenditure (TDEE): This is the total number of calories you burn per day including all physical movement and exercise. This number is used to determine your maintenance calories.

The Mifflin-St Jeor Equation

This calculator uses the Mifflin-St Jeor equation, which is widely considered the most accurate formula for predicting BMR in healthy adults. The logic follows these formulas:

  • For Men: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
  • For Women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161

Example Calculation

Let's look at a realistic scenario for a 30-year-old male weighing 80 kg and standing 180 cm tall who is moderately active:

  1. BMR Calculation: (10 × 80) + (6.25 × 180) – (5 × 30) + 5 = 1,780 kcal.
  2. TDEE Calculation: 1,780 (BMR) × 1.55 (Moderately Active) = 2,759 kcal per day.

To maintain weight, this individual should consume approximately 2,759 calories. To lose weight, a deficit (e.g., 2,200 calories) would be required.

function calculateMetabolism() { var gender = document.getElementById("gender").value; var age = parseFloat(document.getElementById("age").value); var weight = parseFloat(document.getElementById("weight").value); var height = parseFloat(document.getElementById("height").value); var activity = parseFloat(document.getElementById("activity").value); var resultArea = document.getElementById("result-area"); var bmrDisplay = document.getElementById("bmr-result"); var tdeeDisplay = document.getElementById("tdee-result"); if (isNaN(age) || isNaN(weight) || isNaN(height) || age <= 0 || weight <= 0 || height <= 0) { alert("Please enter valid numbers for age, weight, and height."); return; } var bmr = 0; // Mifflin-St Jeor Equation if (gender === "male") { bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5; } else { bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161; } var tdee = bmr * activity; bmrDisplay.innerHTML = Math.round(bmr).toLocaleString(); tdeeDisplay.innerHTML = Math.round(tdee).toLocaleString(); resultArea.style.display = "block"; // Smooth scroll to result resultArea.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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