How Do You Calculate Calories

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Daily Calorie Calculator

Estimate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).

Sedentary (little or no exercise) Lightly active (light exercise 1-3 days/week) Moderately active (moderate exercise 3-5 days/week) Very active (hard exercise 6-7 days/week) Extra active (very hard exercise & physical job)

Your Results

Basal Metabolic Rate (BMR): calories/day

Maintenance Calories (TDEE): calories/day


Note: These results are based on the Mifflin-St Jeor Equation, widely considered the most accurate formula for estimating calorie needs.

Understanding How to Calculate Calories

Determining your daily calorie needs is the foundation of any successful weight management plan, whether your goal is to lose fat, build muscle, or maintain your current physique. But how do we actually calculate these numbers?

1. Basal Metabolic Rate (BMR)

Your BMR is the number of calories your body burns at rest to perform basic life-sustaining functions like breathing, circulation, and cell production. Even if you stayed in bed all day, your body would still require these calories to function.

The calculator above uses the Mifflin-St Jeor Equation:

  • 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

2. Total Daily Energy Expenditure (TDEE)

Your TDEE is the total number of calories you burn each day when exercise and daily movement are factored in. This is also known as your "Maintenance Calories." To calculate TDEE, we multiply your BMR by an activity multiplier (ranging from 1.2 for sedentary individuals to 1.9 for elite athletes).

Real-World Example

Let's look at a 35-year-old male who weighs 85kg and is 180cm tall:

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

Adjusting for Your Goals

Once you know 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 activity = parseFloat(document.getElementById('activity').value); var genderElements = document.getElementsByName('gender'); var gender; for (var i = 0; i < genderElements.length; i++) { if (genderElements[i].checked) { gender = genderElements[i].value; break; } } if (!age || !weight || !height || age <= 0 || weight <= 0 || height <= 0) { alert("Please enter valid positive numbers for age, weight, and height."); return; } var bmr; if (gender === 'male') { // Mifflin-St Jeor for Men bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5; } else { // Mifflin-St Jeor for Women bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161; } var tdee = bmr * activity; document.getElementById('bmrValue').innerText = Math.round(bmr).toLocaleString(); document.getElementById('tdeeValue').innerText = Math.round(tdee).toLocaleString(); document.getElementById('calorieResult').style.display = 'block'; // Smooth scroll to result document.getElementById('calorieResult').scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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