My Metabolic Rate Calculator

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Metabolic Rate & TDEE Calculator

Male Female
Sedentary (Little to no exercise) Lightly Active (1-3 days/week) Moderately Active (3-5 days/week) Very Active (6-7 days/week) Extra Active (Very physical job/2x training)
Basal Metabolic Rate (BMR): 0
Daily Maintenance Calories (TDEE): 0
*BMR represents calories burned at rest. TDEE includes your activity level.

Understanding Your Metabolic Rate

Your metabolic rate is the rate at which your body burns energy (calories) to maintain vital functions like breathing, circulating blood, and cell production. This calculator uses the Mifflin-St Jeor Equation, which is widely considered the most accurate formula for estimating metabolic needs in healthy adults.

BMR vs. TDEE: What is the Difference?

Basal Metabolic Rate (BMR) is the number of calories your body needs to function if you were to stay in bed all day. Even when resting, your body uses energy for things like your heartbeat and brain function.

Total Daily Energy Expenditure (TDEE) is an estimate of how many calories you burn per day when exercise is taken into account. This is the number you should use as a baseline for weight management.

How to Use These Results

  • Weight Maintenance: Consume your TDEE in calories daily.
  • Weight Loss: Consume 250–500 calories less than your TDEE daily.
  • Weight Gain: Consume 250–500 calories more than your TDEE daily.

Typical Example

Consider a 35-year-old male who weighs 85kg and is 180cm tall. If he is moderately active, his calculation would look like this:

  • BMR Calculation: (10 × 85) + (6.25 × 180) – (5 × 35) + 5 = 1,805 calories.
  • TDEE Calculation: 1,805 × 1.55 = 2,798 calories per day to maintain weight.

Factors That Influence Metabolism

While this calculator provides a highly accurate estimate, several factors can influence your actual metabolic rate:

  1. Muscle Mass: Muscle tissue burns more calories at rest than fat tissue. Strength training can increase your BMR.
  2. Age: Metabolic rate typically slows down as we age due to the loss of lean muscle mass.
  3. Hormones: Thyroid issues or hormonal imbalances can significantly speed up or slow down metabolism.
  4. Thermic Effect of Food: Digesting protein requires more energy than digesting fats or carbohydrates.
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 bmr = 0; if (!age || !weight || !height || age <= 0 || weight <= 0 || height <= 0) { alert("Please enter valid positive numbers for age, weight, and height."); return; } // 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; document.getElementById("bmr-result").innerText = Math.round(bmr).toLocaleString() + " kcal/day"; document.getElementById("tdee-result").innerText = Math.round(tdee).toLocaleString() + " kcal/day"; document.getElementById("results").style.display = "block"; }

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