Weight Loss Calculator

What Is the Weight Loss Calculator?

The Weight Loss Calculator helps you determine how much weight you should lose to reach a healthy BMI range. By entering your age, gender, height, current weight, and activity level, you get a personalized weight loss plan with timeline estimates and daily calorie targets. This tool uses the Mifflin-St Jeor equation to calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE), then maps out a realistic weight loss journey based on your chosen pace.

How to Use This Tool

Enter your details - Provide your age, gender, height, and current weight. You can switch between metric (cm/kg) and imperial (ft/in, lbs) units.
Select your activity level - Choose the option that best describes your typical weekly physical activity.
Pick a weight loss pace - Select from gentle (0.25 kg/week), moderate (0.5 kg/week), or aggressive (1 kg/week) plans.
View your results - Instantly see your BMI, healthy weight range, the amount of weight to lose, and an estimated timeline to reach your goal.

Health Indicators Explained

Body Mass Index (BMI)

Body Mass Index is a screening tool that estimates body fat based on height and weight. The World Health Organization classifies BMI into these categories:

Underweight: BMI less than 18.5
Normal weight: BMI between 18.5 and 24.9
Overweight: BMI between 25 and 29.9
Obese: BMI of 30 or higher

Basal Metabolic Rate (BMR)

Your BMR is the number of calories your body needs at complete rest to maintain vital functions like breathing, circulation, and cell production. The Weight Loss Calculator uses the Mifflin-St Jeor equation, which is widely considered the most accurate BMR formula:

For men: $BMR = 10 \times weight(kg) + 6.25 \times height(cm) - 5 \times age(y) + 5$

For women: $BMR = 10 \times weight(kg) + 6.25 \times height(cm) - 5 \times age(y) - 161$

Total Daily Energy Expenditure (TDEE)

TDEE is your BMR multiplied by an activity factor that accounts for the calories you burn through physical activity. This is the total number of calories you burn each day. To lose weight, you need to consume fewer calories than your TDEE.

Weight Loss Pace Options

Gentle (0.25 kg / 0.5 lb per week): A 250-calorie daily deficit. Ideal for those who want a slow, sustainable approach with minimal hunger and fatigue.
Moderate (0.5 kg / 1 lb per week): A 500-calorie daily deficit. This is the most commonly recommended pace by health organizations for safe, steady weight loss.
Aggressive (1 kg / 2 lb per week): A 1000-calorie daily deficit. Suitable only for individuals with significant weight to lose, and should be done under medical supervision.

Related Health and Fitness Calculators

Support your weight loss journey with complementary tools like the Calorie Calculator for daily calorie needs, the BMI Calculator for body mass index tracking, the BMR Calculator for resting metabolic rate, the TDEE Calculator for total energy expenditure, and the Macro Calculator for macronutrient targets. Track body composition with the Body Fat Calculator and daily hydration with the Water Intake Calculator.

Frequently Asked Questions

Is this Weight Loss Calculator accurate?

The calculator uses the clinically validated Mifflin-St Jeor equation for BMR estimation, which has an accuracy rate of about 70% within 10% of actual BMR. Individual results may vary based on genetics, body composition, metabolic health, and other factors. Use the results as a guideline and consult with a healthcare provider for personalized advice.

How much weight can I safely lose per week?

Health experts generally recommend losing 0.5 to 1 kg (1 to 2 lbs) per week. Losing weight too quickly can lead to muscle loss, nutritional deficiencies, gallstones, and a slower metabolism. The moderate pace option in this calculator follows this safe range.

What if my BMI is already in the healthy range?

If your BMI falls between 18.5 and 24.9, you are within the healthy weight range. The calculator will show a message indicating that you are at a healthy weight and encourage you to maintain your current lifestyle rather than pursue weight loss.

Why do I need to enter my activity level?

Your activity level directly affects your Total Daily Energy Expenditure (TDEE). A more active person burns more calories throughout the day, which means they can eat more while still maintaining a calorie deficit. Using the correct activity level ensures your calorie targets and timeline are realistic.

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the minimum calories your body needs at rest to survive. TDEE (Total Daily Energy Expenditure) adds the calories burned through movement, exercise, and daily activities. Your weight loss calorie target is based on TDEE minus the deficit, not BMR.

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