Sedentary (little to 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 a week)
Extra active (very hard exercise/sports & physical job or 2x training)
Understanding Your Calorie Needs for Bodybuilding
Determining your daily calorie intake is fundamental to achieving your bodybuilding goals, whether they involve building muscle (bulking) or losing fat (cutting). This calculator is based on the principles of calculating your Basal Metabolic Rate (BMR) and then adjusting it based on your activity level to estimate your Total Daily Energy Expenditure (TDEE).
Basal Metabolic Rate (BMR)
Your BMR is the number of calories your body burns at rest to maintain basic life functions like breathing, circulation, and cell production. The most commonly used formula for BMR is the Mifflin-St Jeor equation, which is generally considered more accurate than the older Harris-Benedict equation.
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
In this calculator, we use these standard formulas to get your baseline metabolic rate.
Total Daily Energy Expenditure (TDEE)
Your TDEE is the total number of calories you burn in a day, including your BMR and the calories burned through physical activity. This is calculated by multiplying your BMR by an activity factor:
Sedentary: BMR x 1.2 (little to no exercise)
Lightly active: BMR x 1.375 (light exercise/sports 1-3 days/week)
Moderately active: BMR x 1.55 (moderate exercise/sports 3-5 days/week)
Very active: BMR x 1.725 (hard exercise/sports 6-7 days a week)
Extra active: BMR x 1.9 (very hard exercise/sports & physical job or 2x training)
The resulting TDEE is your estimated maintenance calorie level – the calories you need to consume to stay at your current weight.
Using the Calculator for Bodybuilding Goals
Bulking (Muscle Gain):
To build muscle, you need to be in a caloric surplus. This means consuming more calories than your TDEE. A common recommendation is to add 250-500 calories to your TDEE. Start conservatively (e.g., +250 calories) and monitor your progress. If you're not gaining weight or muscle at a satisfactory rate, gradually increase your intake.
Formula: TDEE + (250 to 500) calories = Bulking Calorie Target
Cutting (Fat Loss):
To lose fat, you need to be in a caloric deficit. This means consuming fewer calories than your TDEE. A common recommendation is to subtract 250-500 calories from your TDEE. Aim for a sustainable fat loss of about 0.5-1 kg (1-2 lbs) per week. A deficit that's too large can lead to muscle loss and extreme fatigue.
Formula: TDEE – (250 to 500) calories = Cutting Calorie Target
Disclaimer: This calculator provides an estimate. Individual metabolism and responses can vary. It's crucial to track your progress, adjust your intake based on results, and consult with a healthcare professional or a certified nutritionist for personalized advice.
function calculateCalories() {
var weight = parseFloat(document.getElementById("weight").value);
var height = parseFloat(document.getElementById("height").value);
var age = parseFloat(document.getElementById("age").value);
var gender = document.getElementById("gender").value;
var activityLevel = parseFloat(document.getElementById("activityLevel").value);
var bmr = 0;
var resultDiv = document.getElementById("result");
if (isNaN(weight) || isNaN(height) || isNaN(age) || weight <= 0 || height <= 0 || age <= 0) {
resultDiv.innerHTML = "Please enter valid numbers for weight, height, and age.";
resultDiv.style.backgroundColor = "#dc3545"; /* Error red */
resultDiv.style.display = "block";
return;
}
if (gender === "male") {
bmr = (10 * weight) + (6.25 * height) – (5 * age) + 5;
} else { // female
bmr = (10 * weight) + (6.25 * height) – (5 * age) – 161;
}
var tdee = bmr * activityLevel;
// Display results for maintenance, bulking, and cutting
var maintenanceCalories = Math.round(tdee);
var bulkingCalories = Math.round(tdee + 300); // Mid-point for bulking surplus
var cuttingCalories = Math.round(tdee – 300); // Mid-point for cutting deficit
resultDiv.innerHTML =
"Maintenance Calories: " + maintenanceCalories + " kcal" +
"(Target for weight maintenance)" +
"Bulking Calories: " + bulkingCalories + " kcal" +
"(Target for muscle gain)" +
"Cutting Calories: " + cuttingCalories + " kcal" +
"(Target for fat loss)";
resultDiv.style.backgroundColor = "#28a745"; /* Success green */
resultDiv.style.display = "block";
}