Use this calculator to estimate your daily calorie needs for bodybuilding, whether your goal is maintenance, bulking, or cutting. It takes into account your basal metabolic rate (BMR), activity level, and specific goals to provide a personalized calorie target.
kg
lbs
cm
inches
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 a week)
Extra Active (very hard exercise/physical job)
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function calculateBodybuildingCalories() {
var age = parseFloat(document.getElementById('age').value);
var gender = document.querySelector('input[name="gender"]:checked').value;
var weight = parseFloat(document.getElementById('weight').value);
var weightUnit = document.getElementById('weightUnit').value;
var height = parseFloat(document.getElementById('height').value);
var heightUnit = document.getElementById('heightUnit').value;
var bodyFat = parseFloat(document.getElementById('bodyFat').value);
var activityMultiplier = parseFloat(document.getElementById('activityLevel').value);
var goal = document.querySelector('input[name="goal"]:checked').value;
var resultDiv = document.getElementById('calorieResult');
// Input validation
if (isNaN(age) || age <= 0 || isNaN(weight) || weight <= 0 || isNaN(height) || height <= 0) {
resultDiv.innerHTML = 'Please enter valid positive numbers for age, weight, and height.';
return;
}
if (!isNaN(bodyFat) && (bodyFat 60)) {
resultDiv.innerHTML = 'Please enter a realistic body fat percentage (e.g., 5-40%).';
return;
}
// Convert units to metric for calculations
var weightKg = (weightUnit === 'lbs') ? weight * 0.453592 : weight;
var heightCm = (heightUnit === 'inches') ? height * 2.54 : height;
var bmr;
// Calculate BMR using Katch-McArdle if Body Fat % is provided, otherwise Mifflin-St Jeor
if (!isNaN(bodyFat) && bodyFat > 0) {
// Katch-McArdle Formula: BMR = 370 + (21.6 * Lean Body Mass in kg)
var leanBodyMassKg = weightKg * (1 – (bodyFat / 100));
bmr = 370 + (21.6 * leanBodyMassKg);
} else {
// 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;
}
}
var tdee = bmr * activityMultiplier;
var calorieGoal;
var goalDescription = "";
switch (goal) {
case 'maintenance':
calorieGoal = tdee;
goalDescription = "to maintain your current weight";
break;
case 'bulking':
calorieGoal = tdee + 300; // Common surplus for bulking
goalDescription = "for a lean bulk (gain muscle)";
break;
case 'cutting':
calorieGoal = tdee – 500; // Common deficit for cutting
goalDescription = "for a cut (lose fat)";
break;
}
// Ensure calorie goal doesn't go too low for cutting
if (goal === 'cutting' && calorieGoal < 1200 && gender === 'female') {
calorieGoal = 1200;
goalDescription += " (minimum 1200 calories for women)";
} else if (goal === 'cutting' && calorieGoal < 1500 && gender === 'male') {
calorieGoal = 1500;
goalDescription += " (minimum 1500 calories for men)";
}
resultDiv.innerHTML = `
Your Estimated Daily Calorie Needs:
Your Basal Metabolic Rate (BMR): ${Math.round(bmr)} calories/day
Your Total Daily Energy Expenditure (TDEE): ${Math.round(tdee)} calories/day
Based on your goal of ${goal}, your estimated daily calorie intake ${goalDescription} is: ${Math.round(calorieGoal)} calories/dayNote: These are estimates. Individual needs may vary based on metabolism, training intensity, and other factors. Adjust as needed based on your progress.
`;
}
Understanding Your Calorie Needs for Bodybuilding
Achieving your bodybuilding goals, whether it's gaining muscle (bulking), losing fat (cutting), or maintaining your physique, hinges significantly on your daily calorie intake. This calculator provides a starting point by estimating your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).
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. It's the minimum energy required to keep your body functioning if you were to do nothing but lie in bed all day. The calculator uses either the Mifflin-St Jeor equation (for general use) or the Katch-McArdle formula (if you provide your body fat percentage, which is more accurate for lean individuals).
Mifflin-St Jeor Equation: A widely accepted formula that considers age, gender, weight, and height.
Katch-McArdle Formula: Considered more accurate for bodybuilders and athletes as it accounts for lean body mass, which is a better indicator of metabolic activity than total body weight.
Total Daily Energy Expenditure (TDEE)
Your TDEE is the total number of calories your body burns in a 24-hour period, including your BMR, the thermic effect of food (calories burned during digestion), and the energy expended during physical activity. The calculator applies an activity multiplier to your BMR to estimate your TDEE.
Sedentary: Little to no exercise.
Lightly Active: Light exercise or sports 1-3 days per week.
Moderately Active: Moderate exercise or sports 3-5 days per week.
Very Active: Hard exercise or sports 6-7 days per week.
Extra Active: Very hard exercise, a physically demanding job, or training twice a day.
Setting Your Calorie Goal
Once your TDEE is estimated, the calculator adjusts it based on your bodybuilding goal:
Maintenance: Your calorie goal is approximately your TDEE. This is for maintaining your current weight and physique.
Bulking: To gain muscle mass, you need to consume more calories than your TDEE. The calculator adds a moderate surplus (e.g., 300 calories) to promote muscle growth while minimizing excessive fat gain.
Cutting: To lose body fat, you need to consume fewer calories than your TDEE. The calculator creates a moderate deficit (e.g., 500 calories) to encourage fat loss while preserving muscle.
Important Considerations
Remember that these calculations provide an estimate. Individual metabolic rates can vary, and factors like genetics, sleep, stress, and specific training intensity can influence your actual calorie needs. It's crucial to:
Monitor Progress: Track your weight, body measurements, and how you feel. Adjust your calorie intake by 100-200 calories every 1-2 weeks based on your results.
Prioritize Macronutrients: While total calories are important, the distribution of protein, carbohydrates, and fats (macros) is equally vital for bodybuilding.
Stay Consistent: Consistency in both diet and training is key to achieving long-term bodybuilding success.
Example Scenarios:
Let's consider a 30-year-old male, 80kg (176 lbs), 175cm (5'9″), moderately active, with 15% body fat:
Maintenance: His BMR might be around 1700-1800 calories. With a moderate activity level, his TDEE could be approximately 2600-2800 calories. For maintenance, he'd aim for this range.
Bulking: To bulk, he might add 300 calories, targeting around 2900-3100 calories per day.
Cutting: To cut, he might subtract 500 calories, aiming for 2100-2300 calories per day.
These examples highlight how the calculator helps tailor calorie goals to specific bodybuilding objectives.