How to Calculate Calories

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Daily Calorie Intake Calculator

Estimate your maintenance calories based on the Mifflin-St Jeor Equation.

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

Your Results

Your Basal Metabolic Rate (BMR) is: calories/day

Your Total Daily Energy Expenditure (TDEE) is: calories/day

To maintain weight: Consume calories. To lose weight (0.5kg/week): Consume calories.

How to Calculate Calories: Understanding BMR and TDEE

Calculating your calorie needs is the fundamental first step in any fitness or weight management journey. Whether you want to lose fat, build muscle, or maintain your current physique, you must first understand how much energy your body burns in a day.

1. Basal Metabolic Rate (BMR)

Your BMR is the number of calories your body burns just to keep you alive—breathing, circulating blood, and maintaining organ function—while at complete rest. This calculator uses the Mifflin-St Jeor Equation, widely considered the most accurate formula for modern lifestyles.

  • 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

2. Total Daily Energy Expenditure (TDEE)

TDEE is the total amount of calories you burn per day once physical activity is accounted for. We calculate this by multiplying your BMR by an activity factor:

  • Sedentary (1.2): Office job, minimal movement.
  • Lightly Active (1.375): Light exercise or walking 1-3 days a week.
  • Moderately Active (1.55): Moderate exercise or sports 3-5 days a week.
  • Very Active (1.725): Hard exercise or physical labor 6-7 days a week.

Example Calculation

Profile: Male, 30 years old, 80kg, 180cm, Moderately Active.

BMR Calculation: (10 × 80) + (6.25 × 180) – (5 × 30) + 5 = 1,780 calories.

TDEE Calculation: 1,780 × 1.55 = 2,759 calories per day.

In this example, the individual needs 2,759 calories to maintain his weight. To lose weight, he would typically subtract 500 calories (approx. 2,259 total).

Adjusting for Your Goals

Once you have your TDEE, you can adjust your intake based on your goals:

  • Weight Loss: Aim for a deficit of 250-500 calories below your TDEE.
  • Weight Gain: Aim for a surplus of 250-500 calories above your TDEE.
  • Maintenance: Eat as close to your TDEE as possible.
function calculateCalories() { var age = parseFloat(document.getElementById("age").value); var weight = parseFloat(document.getElementById("weight").value); var height = parseFloat(document.getElementById("height").value); var gender = document.getElementById("gender").value; var activity = parseFloat(document.getElementById("activity").value); var resultDiv = document.getElementById("calorieResult"); if (!age || !weight || !height || age <= 0 || weight <= 0 || height <= 0) { alert("Please enter valid positive numbers for age, weight, and height."); return; } var bmr = 0; 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; var maintenance = Math.round(tdee); var weightLoss = Math.round(tdee – 500); document.getElementById("bmrVal").innerHTML = Math.round(bmr).toLocaleString(); document.getElementById("tdeeVal").innerHTML = maintenance.toLocaleString(); document.getElementById("maintVal").innerHTML = maintenance.toLocaleString(); document.getElementById("loseVal").innerHTML = weightLoss.toLocaleString(); resultDiv.style.display = "block"; resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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