Calculate your future weight based on daily calorie intake.
Male
Female
Sedentary (Office job)
Lightly Active (1-3 days/week)
Moderately Active (3-5 days/week)
Very Active (6-7 days/week)
Extra Active (Physical labor/Pro athlete)
Weekly Weight Projection
Week
Predicted Weight (lbs)
Total Lost
function calculateLosertown() {
var gender = document.getElementById('lt-gender').value;
var weightLbs = parseFloat(document.getElementById('lt-weight').value);
var heightIn = parseFloat(document.getElementById('lt-height').value);
var age = parseFloat(document.getElementById('lt-age').value);
var activity = parseFloat(document.getElementById('lt-activity').value);
var intake = parseFloat(document.getElementById('lt-intake').value);
if (isNaN(weightLbs) || isNaN(heightIn) || isNaN(age) || isNaN(intake)) {
alert("Please fill in all fields with valid numbers.");
return;
}
// Convert to Metric for Mifflin-St Jeor
var weightKg = weightLbs * 0.453592;
var heightCm = heightIn * 2.54;
var bmr;
if (gender === 'male') {
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) + 5;
} else {
bmr = (10 * weightKg) + (6.25 * heightCm) – (5 * age) – 161;
}
var tdee = bmr * activity;
var dailyDeficit = tdee – intake;
var summaryText = "Your estimated TDEE (Maintenance Calories) is " + Math.round(tdee) + " calories per day. ";
if (dailyDeficit > 0) {
summaryText += "With an intake of " + intake + ", you will lose approximately " + ((dailyDeficit * 7) / 3500).toFixed(2) + " lbs per week.";
} else {
summaryText += "Warning: Your intake is higher than your expenditure. You may gain weight.";
}
document.getElementById('lt-summary-text').innerHTML = summaryText;
var tableBody = document.getElementById('lt-table-body');
tableBody.innerHTML = "";
var currentWeight = weightLbs;
var startingWeight = weightLbs;
for (var i = 1; i <= 12; i++) {
// Recalculate BMR/TDEE each week as weight drops
var currentWeightKg = currentWeight * 0.453592;
var currentBmr;
if (gender === 'male') {
currentBmr = (10 * currentWeightKg) + (6.25 * heightCm) – (5 * age) + 5;
} else {
currentBmr = (10 * currentWeightKg) + (6.25 * heightCm) – (5 * age) – 161;
}
var currentTdee = currentBmr * activity;
var weeklyDeficit = (currentTdee – intake) * 7;
var lbsLostThisWeek = weeklyDeficit / 3500;
currentWeight -= lbsLostThisWeek;
var row = "
Understanding the Losertown Calorie Calculator Logic
The Losertown Calorie Calculator is a cult-favorite tool in the fitness and weight loss community. Unlike standard calculators that simply tell you your maintenance calories, the "Losertown" style logic projects your weight loss trajectory over several weeks or months. This helps users visualize the impact of their caloric deficit on their future body weight.
How the Calculation Works
The math behind this predictor relies on the Mifflin-St Jeor Equation, which is widely considered the most accurate way to estimate Basal Metabolic Rate (BMR). Your BMR is the number of calories your body burns just to stay alive while at rest.
Step 1: Calculate BMR. This uses your age, weight, height, and biological sex.
Step 2: Determine TDEE. Your BMR is multiplied by an activity factor (1.2 for sedentary up to 1.9 for elite athletes) to find your Total Daily Energy Expenditure.
Step 3: The Deficit. We subtract your "Daily Calorie Intake" from your TDEE.
Step 4: The 3,500 Rule. Scientific consensus generally suggests that a deficit of 3,500 calories equals roughly 1 pound of fat loss.
Dynamic Recalculation
What makes our Losertown-style calculator unique is that it adjusts for your new weight every week. As you lose weight, your BMR naturally decreases because there is less of "you" for your body to maintain. This calculator accounts for that metabolic slowdown, providing a more realistic timeline than a static calculation would.
Example Weight Loss Scenario
Imagine a 30-year-old female who is 5'6″ (66 inches) and weighs 180 lbs. If she has a sedentary job and decides to eat 1,500 calories per day:
Her starting TDEE is approximately 1,860 calories.
Her daily deficit is 360 calories (1,860 – 1,500).
In Week 1, she would lose about 0.72 lbs.
By Week 12, as her weight drops, her TDEE will also drop slightly, making the weight loss slightly slower each week.
Important Considerations
While the Losertown math is mathematically sound, the human body is complex. Water retention, hormonal changes, and muscle gain can all cause the scale to fluctuate differently than the predicted chart. Use this tool as a motivational roadmap rather than an absolute guarantee. Always consult with a healthcare professional before starting a significant calorie-restricted diet.