Sedentary (little or no exercise)
Lightly Active (light exercise/sports 1-3 days/week)
Moderately Active (moderate exercise/sports 3-5 days/week)
Very Active (hard exercise/sports 6-7 days/week)
Extra Active (very hard exercise/sports & physical job)
Your Daily Calorie Target:
Understanding the 21 Day Fix Calorie Calculator
The 21 Day Fix program, developed by Autumn Calabrese, is a popular fitness and nutrition plan designed to help individuals achieve their weight loss goals in a structured yet flexible way. A crucial component of the program is determining a personalized daily calorie target, which is then used to guide food choices using the program's color-coded container system. This calculator helps you estimate that target.
The Math Behind the Calculation
The 21 Day Fix calorie calculator typically uses a variation of the Mifflin-St Jeor equation, which is a widely accepted formula for estimating Basal Metabolic Rate (BMR) – the number of calories your body burns at rest. The formula is then adjusted for your activity level to determine your Total Daily Energy Expenditure (TDEE), which is then further adjusted for weight loss.
Step 1: Calculate Basal Metabolic Rate (BMR)
For Men:
BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) + 5
For Women:
BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) – 161
This calculator first converts your weight from pounds (lbs) to kilograms (kg) by dividing by 2.20462. It also converts your height from feet and inches into centimeters (cm) using the conversion: (feet * 12 + inches) * 2.54.
Step 2: Calculate Total Daily Energy Expenditure (TDEE)
TDEE = BMR x Activity Level Multiplier
The activity level multipliers are standard values used to account for the calories burned through daily activities and exercise.
Step 3: Adjust for 21 Day Fix Calorie Target
The 21 Day Fix program has specific calorie ranges. For weight loss, the TDEE is typically reduced by a set amount. This calculator will provide a target calorie range that aligns with the program's guidelines, usually within specific tiers. The output of this calculator provides an estimated starting point for your calorie target.
*Note: This calculator provides an estimate. For precise nutritional guidance and personalized plans, it's always recommended to consult with a qualified healthcare professional or a registered dietitian.*
How to Use This Calculator
To get your estimated daily calorie target for the 21 Day Fix program, please provide the following information accurately:
Weight: Your current weight in pounds (lbs).
Height: Your height in feet and inches.
Age: Your age in years.
Gender: Select your gender (Male or Female).
Activity Level: Choose the option that best describes your typical weekly physical activity.
Once you enter these details and click "Calculate My Calories," the calculator will provide your recommended daily calorie intake to help you get started with the 21 Day Fix program.
function calculateCalories() {
var weightLbs = parseFloat(document.getElementById('weight').value);
var heightFeet = parseFloat(document.getElementById('heightFeet').value);
var heightInches = parseFloat(document.getElementById('heightInches').value);
var age = parseFloat(document.getElementById('age').value);
var gender = document.getElementById('gender').value;
var activityLevel = parseFloat(document.getElementById('activityLevel').value);
// Input validation
if (isNaN(weightLbs) || isNaN(heightFeet) || isNaN(heightInches) || isNaN(age) || isNaN(activityLevel) || weightLbs <= 0 || heightFeet < 0 || heightInches < 0 || age <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
// Convert weight to kg
var weightKg = weightLbs / 2.20462;
// Convert height to cm
var totalHeightInches = (heightFeet * 12) + heightInches;
var heightCm = totalHeightInches * 2.54;
var bmr = 0;
// Calculate BMR using Mifflin-St Jeor Equation
if (gender === 'male') {
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) + 5;
} else { // female
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) – 161;
}
// Calculate TDEE
var tdee = bmr * activityLevel;
// Apply 21 Day Fix calorie adjustment for weight loss
// This is a general adjustment; actual 21DF targets are in specific ranges.
// The calculator aims to provide a starting point within typical loss ranges.
var calorieTarget = tdee – 500; // General deficit for weight loss
// Ensure calorie target doesn't go below a safe minimum (e.g., 1200 for women, 1500 for men)
if (gender === 'female' && calorieTarget < 1200) {
calorieTarget = 1200;
} else if (gender === 'male' && calorieTarget < 1500) {
calorieTarget = 1500;
}
// Round to the nearest whole number
calorieTarget = Math.round(calorieTarget);
document.getElementById('calorieResult').innerText = calorieTarget + " calories";
document.getElementById('result').style.display = 'block';
}