Metabolic Rate Calculator with Exercise

Advanced Metabolic Rate & Activity Calculator

Male Female

Sedentary (Little/no exercise) Light (1-3 days/week) Moderate (3-5 days/week) Active (6-7 days/week) Extra Active (Physical job/2x training)

Your Results

Basal Metabolic Rate (BMR)

0

calories/day

Daily TDEE (With Exercise)

0

calories/day

To Maintain Weight: 0 kcal/day
To Lose Weight (0.5kg/week): 0 kcal/day
To Gain Weight (0.5kg/week): 0 kcal/day

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); if (isNaN(age) || isNaN(weight) || isNaN(height)) { alert("Please fill in all fields with valid numbers."); 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; document.getElementById("bmr-output").innerText = Math.round(bmr).toLocaleString(); document.getElementById("tdee-output").innerText = Math.round(tdee).toLocaleString(); document.getElementById("maintain-cal").innerText = Math.round(tdee).toLocaleString(); document.getElementById("lose-cal").innerText = Math.round(tdee – 500).toLocaleString(); document.getElementById("gain-cal").innerText = Math.round(tdee + 500).toLocaleString(); document.getElementById("metabolic-results").style.display = "block"; }

Understanding Your Metabolic Rate and Exercise

Your metabolic rate is the speed at which your body burns energy (calories) to maintain vital functions like breathing, circulating blood, and cell repair. When you incorporate exercise into your routine, your Total Daily Energy Expenditure (TDEE) increases significantly. Using a metabolic rate calculator with exercise allows you to accurately predict how many calories you need based on your physical activity level.

BMR vs. TDEE: What is the Difference?

The calculation above provides two primary metrics:

• Basal Metabolic Rate (BMR): This is the number of calories your body would burn if you stayed in bed all day doing absolutely nothing. It is influenced by your age, height, weight, and gender.
• Total Daily Energy Expenditure (TDEE): This is the total number of calories you burn per day once physical activity is added. This calculator uses the Mifflin-St Jeor equation and applies an activity multiplier to estimate this value.

How Exercise Affects Metabolism

Exercise impacts your metabolic rate in two ways. First, the immediate exertion burns calories during the activity. Second, consistent strength training increases muscle mass. Because muscle tissue is more metabolically active than fat tissue, having a higher muscle-to-fat ratio increases your BMR, meaning you burn more calories even while resting.

Calculation Example

Consider a 30-year-old male who weighs 80kg and is 180cm tall. Using the formula:

BMR = (10 × 80) + (6.25 × 180) – (5 × 30) + 5 = 1,780 calories.
If he exercises 3 times a week (Moderate Activity – 1.55 multiplier):
TDEE = 1,780 × 1.55 = 2,759 calories per day.

Daily Activity Levels Explained

Activity Level	Description
Sedentary	Office work, very little intentional movement.
Lightly Active	Light exercise or walking 1-3 days per week.
Moderately Active	Moderate exercise or sports 3-5 days per week.
Very Active	Intense exercise or sports 6-7 days per week.

Optimizing for Weight Goals

Once you know your TDEE, you can adjust your intake based on your goals. For weight loss, a deficit of 500 calories per day typically results in 0.5kg of weight loss per week. For muscle gain, a surplus of 250-500 calories combined with resistance training is recommended. Always consult with a healthcare professional before starting a new diet or exercise regimen.