Weight Loss Calculator by Date

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Weight Loss Calculator by Date

Male Female
Sedentary (Little to no exercise) Lightly Active (1-3 days/week) Moderately Active (3-5 days/week) Very Active (6-7 days/week) Extra Active (Hard labor/training)

How to Plan Your Weight Loss by Date

Planning weight loss with a specific deadline requires a balance between your metabolic rate and a caloric deficit. This calculator uses the Mifflin-St Jeor Equation to determine your Basal Metabolic Rate (BMR) and adjusts it based on your activity level (TDEE).

Key Metrics Explained

  • BMR: The calories your body burns at rest to maintain basic life functions.
  • TDEE: Your Total Daily Energy Expenditure. This is the "maintenance" number. If you eat this amount, your weight stays the same.
  • Caloric Deficit: To lose 1kg of body fat, you typically need a cumulative deficit of approximately 7,700 calories.

Realistic Examples

Scenario Goal Timeframe Avg. Deficit
Steady Loss 5 kg 10 Weeks 550 kcal/day
Aggressive Loss 10 kg 12 Weeks 916 kcal/day

Disclaimer: Consult with a healthcare professional before starting any aggressive weight loss plan. A daily caloric intake below 1,200 for women or 1,500 for men is generally not recommended without medical supervision.

function calculateWeightLoss() { var currentWeight = parseFloat(document.getElementById('currentWeight').value); var goalWeight = parseFloat(document.getElementById('goalWeight').value); var height = parseFloat(document.getElementById('height').value); var age = parseFloat(document.getElementById('age').value); var gender = document.getElementById('gender').value; var activity = parseFloat(document.getElementById('activity').value); var targetDateVal = document.getElementById('targetDate').value; var resultDiv = document.getElementById('weightLossResult'); if (!currentWeight || !goalWeight || !height || !age || !targetDateVal) { alert("Please fill in all fields correctly."); return; } var today = new Date(); var targetDate = new Date(targetDateVal); var timeDiff = targetDate.getTime() – today.getTime(); var dayDiff = Math.ceil(timeDiff / (1000 * 3600 * 24)); if (dayDiff = currentWeight) { alert("Goal weight should be lower than current weight for loss calculation."); return; } // Mifflin-St Jeor Equation var bmr = 0; if (gender === 'male') { bmr = (10 * currentWeight) + (6.25 * height) – (5 * age) + 5; } else { bmr = (10 * currentWeight) + (6.25 * height) – (5 * age) – 161; } var tdee = bmr * activity; var totalWeightToLose = currentWeight – goalWeight; var totalCaloriesToBurn = totalWeightToLose * 7700; // 7700 kcal per 1kg fat var dailyDeficitNeeded = totalCaloriesToBurn / dayDiff; var recommendedDailyIntake = tdee – dailyDeficitNeeded; var statusColor = "#27ae60"; var warningMsg = ""; if (recommendedDailyIntake < 1200) { statusColor = "#e67e22"; warningMsg = "⚠️ Warning: Your daily calorie target is very low. Please consult a doctor. To make this healthier, extend your target date."; } resultDiv.style.display = "block"; resultDiv.style.borderColor = statusColor; var html = "

Your Personalized Plan

"; html += "To reach " + goalWeight + " kg by " + targetDate.toDateString() + " (" + dayDiff + " days):"; html += "
"; html += "
" + Math.round(recommendedDailyIntake) + "Daily Calorie Goal
"; html += "
" + Math.round(dailyDeficitNeeded) + "Daily Deficit (kcal)
"; html += "
" + (totalWeightToLose / (dayDiff / 7)).toFixed(2) + "kg per Week
"; html += "
"; html += "
"; html += "Your estimated maintenance calories (TDEE) are " + Math.round(tdee) + " kcal/day."; html += warningMsg; resultDiv.innerHTML = html; // Smooth scroll to result resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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