Weight Loss Calorie Calculator

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Weight Loss Calorie Calculator
Maintain Weight (TDEE)Mild Weight Loss (0.5 lb/week)Weight Loss (1 lb/week)Extreme Weight Loss (2 lbs/week)
MaleFemale
Sedentary (Office job, no exercise)Lightly Active (Exercise 1-3 days/week)Moderately Active (Exercise 3-5 days/week)Very Active (Exercise 6-7 days/week)Extra Active (Physical job + heavy exercise)
Daily Calorie Target:

— Calories / Day
function calculateWeightLoss(){var age=parseFloat(document.getElementById('age').value);var gender=document.getElementById('gender').value;var weightLbs=parseFloat(document.getElementById('weight').value);var heightIn=parseFloat(document.getElementById('height').value);var activity=parseFloat(document.getElementById('activity').value);var goal=document.getElementById('calc_goal').value;var showSteps=document.getElementById('steps').checked;if(isNaN(age)||isNaN(weightLbs)||isNaN(heightIn)){alert('Please enter valid numeric values for age, weight, and height.');return;}var weightKg=weightLbs*0.453592;var heightCm=heightIn*2.54;var bmr=0;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 target=tdee;var goalText="";if(goal==='mild'){target=tdee-250;goalText="Mild Loss (-0.5lb/wk)";}else if(goal==='lose'){target=tdee-500;goalText="Weight Loss (-1lb/wk)";}else if(goal==='extreme'){target=tdee-1000;goalText="Extreme Loss (-2lb/wk)";}else{goalText="Maintenance";}if(target<1200 && gender==='female'){target=1200;}if(target<1500 && gender==='male'){target=1500;}document.getElementById('resultValue').innerHTML=Math.round(target);var stepsDiv=document.getElementById('detailSteps');if(showSteps){stepsDiv.style.display='block';stepsDiv.innerHTML='Step 1: Metric Conversion
Weight: '+weightKg.toFixed(2)+' kg | Height: '+heightCm.toFixed(2)+' cm

Step 2: BMR (Mifflin-St Jeor)
BMR: '+Math.round(bmr)+' kcal

Step 3: TDEE (Maintenance)
BMR x '+activity+' = '+Math.round(tdee)+' kcal

Step 4: Goal Adjustment
'+goalText+': '+Math.round(target)+' kcal';}else{stepsDiv.style.display='none';}}

How to Use the Weight Loss Calorie Calculator

Understanding your body's energy requirements is the first step toward successful body transformation. This weight loss calorie calculator helps you determine exactly how many calories you should consume daily to reach your target weight safely and effectively. By inputting your personal metrics, the tool calculates your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) to provide a tailored plan.

Age, Gender, Weight, and Height
These biological factors determine your resting metabolism. Men generally require more calories due to higher muscle mass, and metabolism naturally slows as we age.
Activity Level
This represents how much you move daily. A "Sedentary" setting is for those with desk jobs and little exercise, while "Extra Active" is reserved for athletes or those with physically demanding labor jobs.
Weight Goal
Choose between maintaining your current weight or losing weight at different speeds (0.5 lb to 2 lbs per week).

The Science: How It Works

The weight loss calorie calculator utilizes the Mifflin-St Jeor Equation, which is currently considered the gold standard for predicting calorie needs in healthy individuals. The process involves two primary calculations:

BMR (Men) = (10 × weight in kg) + (6.25 × height in cm) – (5 × age) + 5
BMR (Women) = (10 × weight in kg) + (6.25 × height in cm) – (5 × age) – 161

Once the BMR is established, we apply an Activity Multiplier (PAL) to find your TDEE:

  • Sedentary: TDEE = BMR × 1.2
  • Lightly Active: TDEE = BMR × 1.375
  • Moderately Active: TDEE = BMR × 1.55
  • Very Active: TDEE = BMR × 1.725
  • Extra Active: TDEE = BMR × 1.9

Calculation Example

Example: Let's calculate the needs for a 35-year-old male, weighing 200 lbs, 6 feet tall (72 inches), who is moderately active and wants to lose 1 lb per week.

Step-by-step solution:

  1. Convert units: 200 lbs = 90.72 kg | 72 inches = 182.88 cm
  2. Calculate BMR: (10 × 90.72) + (6.25 × 182.88) – (5 × 35) + 5 = 1,880 kcal
  3. Calculate TDEE: 1,880 × 1.55 (Moderate) = 2,914 kcal
  4. Apply Weight Loss Deficit: 2,914 – 500 = 2,414 kcal
  5. Result: Daily target is approximately 2,414 calories.

Common Questions

How many calories should I eat to lose weight?

To lose weight, you must consume fewer calories than you burn. A deficit of 500 calories per day typically results in 1 lb of fat loss per week. However, women should generally not go below 1,200 calories and men not below 1,500 calories per day without medical supervision.

Is this calculator 100% accurate?

While the weight loss calorie calculator uses validated scientific formulas, it provides an estimate. Individual factors like body composition (muscle vs. fat ratio), genetics, and hormonal health can influence your actual calorie burn.

What happens if I eat too few calories?

Extreme calorie restriction can lead to muscle loss, nutrient deficiencies, and a "starvation response" where your metabolism slows down significantly to conserve energy. Sustainable weight loss is usually found in a moderate deficit.

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