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)
Maintain Weight
Lose Weight
Gain Weight
Harris-Benedict (Revised)
Mifflin-St Jeor
Male
Female
Your recommended daily carbohydrate intake is:
— grams
Understanding Carbohydrate Intake for Your Health Goals
Determining the right carbohydrate intake is crucial for achieving various health and fitness goals, whether it's weight management, muscle gain, or simply maintaining a balanced diet. This calculator provides an estimated daily carbohydrate target based on your personal metrics and goals.
How it Works: The Math Behind the Calculator
This calculator first estimates your Basal Metabolic Rate (BMR) – the number of calories your body burns at rest. We use two common formulas for this:
Revised Harris-Benedict Equation (1990):
Men: BMR = (13.397 x weight in kg) + (4.799 x height in cm) – (5.677 x age in years) + 88.362
Women: BMR = (9.247 x weight in kg) + (3.098 x height in cm) – (4.330 x age in years) + 447.593
Mifflin-St Jeor Equation (considered more accurate by many):
Men: BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) + 5
Women: BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) – 161
Next, we calculate your Total Daily Energy Expenditure (TDEE) by multiplying your BMR by an activity factor:
Note: If you entered a target weight different from your current weight, the TDEE calculation will use the target weight for a more accurate long-term calorie estimate for weight loss or gain.
Who Should Use This Calculator?
This calculator is a helpful tool for individuals looking to:
Manage their weight effectively (lose, gain, or maintain).
Understand macronutrient distribution in their diet.
Optimize their nutrition for fitness goals.
Make informed food choices based on carbohydrate targets.
Individuals following various dietary approaches (e.g., balanced diets, moderate-low carb).
Important Considerations:
This calculator provides an estimate. Individual needs can vary based on metabolism, genetics, specific health conditions, and the intensity/type of activity. For personalized dietary advice, it is always recommended to consult with a registered dietitian or a healthcare professional. The quality of carbohydrates consumed (whole grains, fruits, vegetables vs. refined sugars) also plays a significant role in health outcomes.
function calculateCarbs() {
var weightKg = parseFloat(document.getElementById("weightKg").value);
var age = parseFloat(document.getElementById("age").value);
var carbPercentage = parseFloat(document.getElementById("carbPercentage").value);
var activityLevel = document.getElementById("activityLevel").value;
var goal = document.getElementById("goal").value;
var gender = document.getElementById("gender").value;
var bmrMethod = document.getElementById("bmrMethod").value;
var goalWeightKgInput = document.getElementById("goalWeightKg").value;
// Validate inputs
if (isNaN(weightKg) || isNaN(age) || isNaN(carbPercentage)) {
alert("Please enter valid numbers for Weight, Age, and Carbohydrate Percentage.");
return;
}
if (weightKg <= 0 || age <= 0 || carbPercentage 100) {
alert("Please enter realistic values for Weight, Age, and Carbohydrate Percentage.");
return;
}
var heightCm = 170; // Default height, as it's not provided and crucial for BMR. THIS SHOULD BE AN INPUT FIELD IN A REALISTIC SCENARIO.
// For demonstration purposes, let's add a prompt if height is missing, or use a default.
// In a real app, height would be a required input.
if (typeof heightCm === 'undefined' || isNaN(heightCm) || heightCm <= 0) {
var userHeight = prompt("Please enter your height in centimeters (cm) for BMR calculation. Example: 175");
heightCm = parseFloat(userHeight);
if (isNaN(heightCm) || heightCm 0) {
var goalWeightKg = parseFloat(goalWeightKgInput);
// Basic check: if target weight is significantly different, adjust calorie deficit/surplus accordingly.
// For simplicity here, we maintain the fixed 500 cal adjustment. A more precise calculation would involve
// recalculating BMR/TDEE with goalWeightKg.
if (goal === "lose" && goalWeightKg weightKg) {
// Target calories already set to TDEE + 500
} else if (goal === "lose" && goalWeightKg >= weightKg) {
targetCalories = tdee; // No deficit needed if target is same or higher
} else if (goal === "gain" && goalWeightKg <= weightKg) {
targetCalories = tdee; // No surplus needed if target is same or lower
}
}
var carbCalories = targetCalories * (carbPercentage / 100);
var carbGrams = carbCalories / 4; // 4 calories per gram of carbohydrate
document.getElementById("carbResultGrams").textContent = carbGrams.toFixed(1);
}