Use this calculator to estimate your daily caloric and macronutrient needs for weight loss on a ketogenic diet. It helps you determine your Basal Metabolic Rate (BMR), Total Daily Energy Expenditure (TDEE), and then calculates your target calories and macros (carbs, protein, fat) based on your goals.
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/training twice a day)
Understanding Your Keto Macros for Weight Loss
The ketogenic diet is a low-carb, moderate-protein, high-fat eating plan that aims to shift your body's metabolism from burning carbohydrates for fuel to burning fat, a state known as ketosis. This metabolic shift can be highly effective for weight loss, but it requires careful tracking of your macronutrients (carbs, protein, and fat).
How the Calculator Works:
Basal Metabolic Rate (BMR): This is the number of calories your body burns at rest to maintain basic bodily functions (breathing, circulation, cell production). The calculator uses the Mifflin-St Jeor equation, which is widely considered one of the most accurate BMR formulas.
Total Daily Energy Expenditure (TDEE): Your TDEE is your BMR multiplied by an activity factor. It represents the total number of calories you burn in a day, including exercise and daily activities.
Caloric Deficit: To lose weight, you need to consume fewer calories than your TDEE. This calculator allows you to set a percentage deficit (e.g., 15-25%) to create the necessary calorie gap for fat loss. A common deficit for sustainable weight loss is 15-25%.
Macronutrient Breakdown:
Net Carbs: For ketosis, net carb intake is typically kept very low, often between 20-50 grams per day. This calculator uses your specified target.
Protein: Protein is crucial for maintaining muscle mass while losing weight. Too little protein can lead to muscle loss, while too much can potentially kick you out of ketosis (though this is less common than often believed). The calculator estimates protein based on your body weight (typically 1.0-1.2g per kg of body weight for weight loss).
Fat: Once carbs and protein are accounted for, the remaining calories are filled with fat. Fat is the primary energy source on a ketogenic diet and helps with satiety.
Why is this important for Keto?
Accurately calculating your macros is the cornerstone of a successful ketogenic diet for weight loss. Consuming too many carbs will prevent ketosis. Eating too little protein can lead to muscle loss. Not consuming enough fat can leave you hungry and make the diet unsustainable. This calculator provides a personalized starting point, which you can then adjust based on your progress and how you feel.
Example Calculation:
Let's consider a 30-year-old moderately active female, weighing 70 kg (154 lbs) and 170 cm (5'7″) tall, aiming for 20g net carbs and a 20% caloric deficit.
So, for this individual, a starting point would be approximately 1800 calories, with 20g Net Carbs, 77g Protein, and 157g Fat.
Remember, these are estimates. Individual results may vary, and it's always recommended to consult with a healthcare professional or registered dietitian before making significant dietary changes.
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function calculateKetoMacros() {
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 activityLevelMultiplier = parseFloat(document.getElementById("activityLevel").value);
var targetCarbsGrams = parseFloat(document.getElementById("targetCarbs").value);
var deficitPercentage = parseFloat(document.getElementById("deficitPercentage").value);
// Input validation
if (isNaN(age) || age <= 0 ||
isNaN(weight) || weight <= 0 ||
isNaN(height) || height <= 0 ||
isNaN(targetCarbsGrams) || targetCarbsGrams < 0 ||
isNaN(deficitPercentage) || deficitPercentage = 100) {
document.getElementById("result").innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
// Convert units to metric for calculation
var weightKg = (weightUnit === "lbs") ? weight * 0.453592 : weight;
var heightCm = (heightUnit === "inches") ? height * 2.54 : height;
var bmr;
// 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 * activityLevelMultiplier;
var targetCalories = tdee * (1 – (deficitPercentage / 100));
// Macronutrient Calculation
var carbCalories = targetCarbsGrams * 4; // 4 calories per gram of carb
// Protein: 1.0 to 1.2 grams per kg of current body weight is a common range for keto weight loss.
// Let's use 1.1g/kg as a default for this calculator.
var proteinGrams = weightKg * 1.1;
var proteinCalories = proteinGrams * 4; // 4 calories per gram of protein
var fatCalories = targetCalories – carbCalories – proteinCalories;
// Ensure fat calories are not negative (can happen with very high protein/carb targets or extreme deficits)
if (fatCalories < 0) {
fatCalories = 0; // Adjust to 0 if negative, indicating an impossible target
// Optionally, you could adjust protein or carbs down here, but for simplicity, we'll just cap fat.
}
var fatGrams = fatCalories / 9; // 9 calories per gram of fat
// Display results
var resultHtml = "