Weight Loss Calculator 2025

Calorie Deficit & Timeline Calculator

💪 Advanced Weight Loss Calculator

Timeline Prediction - Exact goal achievement date

4 Speed Options - Slow, moderate, aggressive, maximum

Body Composition - Fat vs muscle loss estimate

Safety Warnings - Minimum calorie protection

Enter Your Details

Your Weight Loss Plan

Target Achievement Date

13 May 2026

In 22.0 weeks (5.1 months)

Daily Calorie Target

2201

Deficit: 500 cal/day

Total to Lose

10.0 kg

Weekly Loss

0.45 kg

Body Composition Estimate

Fat Loss

7.5 kg

~75%

Muscle Loss

2.5 kg

~25%

💡 Add strength training to preserve muscle

Compare All Weight Loss Speeds

SpeedDaily CaloriesWeekly LossTime to GoalSafety
Slow & Sustainable 2451 cal0.23 kg/week44.0 weeksVery Safe
Moderate (Recommended) ← Current2201 cal0.45 kg/week22.0 weeksSafe
Aggressive 1951 cal0.68 kg/week14.7 weeksModerate Risk
Maximum (Not Recommended) 1701 cal0.91 kg/week11.0 weeksHigh Risk

What is a Weight Loss Calculator?

A Weight Loss Calculator estimates how long it will take to reach your goal weight based on your calorie deficit. It calculates your daily calorie needs, creates a deficit plan, and predicts the exact date you'll achieve your target weight.

Our calculator provides 4 weight loss speeds (slow, moderate, aggressive, maximum), predicts timeline with exact goal date, compares all deficit options, estimates fat vs muscle loss (body composition), includes safety warnings for minimum calorie intake, and shows weekly progress breakdown.

How to Use

  1. 1Select unit system (metric or imperial)
  2. 2Enter gender, age, current weight & goal weight
  3. 3Add your height and activity level
  4. 4Choose weight loss speed (slow to maximum)
  5. 5Get timeline, daily calories & comparison table

Understanding Calorie Deficit for Weight Loss

What is Calorie Deficit?

A calorie deficit means eating fewer calories than your body burns. This forces your body to use stored fat for energy, resulting in weight loss.

Formula:

Deficit = TDEE - Daily Calorie Intake

1 kg fat = 7,700 calories

How Much Deficit?

250 cal deficit

0.25 kg/week - Very sustainable

500 cal deficit

0.5 kg/week - Recommended

750 cal deficit

0.75 kg/week - Aggressive

1000 cal deficit

1 kg/week - Maximum (risky)

Safe Weight Loss Rate

Healthy, sustainable weight loss is 0.5-1 kg per week (1-2 lbs). Faster loss increases muscle loss and health risks.

0.25-0.5 kg/week: Very safe, sustainable

0.5-1 kg/week: Safe, recommended

⚠️ 1-1.5 kg/week: Aggressive, short-term only

>1.5 kg/week: Unhealthy, muscle loss

Weight Loss Speed Options Explained

Slow & Sustainable

250 cal deficit/day = 0.25 kg/week

✅ Pros:

  • Most sustainable
  • Minimal muscle loss
  • Easy to maintain
  • No hunger issues

❌ Cons:

  • Takes longest time
  • Slow visible results

Moderate (Recommended)

500 cal deficit/day = 0.5 kg/week

✅ Pros:

  • Best balance
  • Sustainable long-term
  • Good visible results
  • Manageable hunger

❌ Cons:

  • Requires consistency
  • Some willpower needed

Aggressive

750 cal deficit/day = 0.75 kg/week

✅ Pros:

  • Faster results
  • Good for kickstart
  • Motivating

❌ Cons:

  • Harder to sustain
  • More hunger
  • Risk of muscle loss

Maximum (Not Recommended)

1000 cal deficit/day = 1 kg/week

✅ Pros:

  • Fastest results
  • Quick kickstart

❌ Cons:

  • High muscle loss
  • Very difficult
  • Health risks
  • Not sustainable

⚠️ Minimum Calorie Requirements (Safety)

Eating too few calories is dangerous and can slow metabolism, cause muscle loss, and lead to nutrient deficiencies. Never go below minimum safe limits.

👨Men - Minimum 1,500 calories/day

Why this minimum?

  • Maintains muscle mass
  • Supports metabolism
  • Provides essential nutrients
  • Prevents hormonal imbalances

👩Women - Minimum 1,200 calories/day

Why this minimum?

  • Protects bone health
  • Maintains menstrual cycle
  • Prevents hair loss
  • Supports immune system

🚫 Dangers of Very Low Calorie Diets (<1200/1500):

  • Severe muscle loss (metabolic damage)
  • Fatigue, weakness, dizziness
  • Hair loss, brittle nails
  • Nutrient deficiencies (vitamins, minerals)
  • Hormonal disruption (thyroid, reproductive)
  • Increased hunger & binge eating risk

Understanding Fat vs Muscle Loss

When you lose weight, you don't just lose fat. Typically, weight loss consists of 75% fat and 25% lean mass (muscle, water, bone). Here's how to maximize fat loss and minimize muscle loss:

✅ How to Preserve Muscle

  • Strength training: Lift weights 2-4x/week to signal muscle retention
  • Protein intake: Eat 1.6-2.2g protein per kg bodyweight daily
  • Moderate deficit: 300-500 cal deficit (not extreme)
  • Adequate sleep: 7-9 hours for muscle recovery
  • Slow weight loss: 0.5-1% bodyweight per week maximum

❌ What Causes Muscle Loss

  • Large calorie deficit: >1000 cal deficit triggers muscle breakdown
  • Low protein: Insufficient amino acids for muscle maintenance
  • No strength training: Body has no reason to keep muscle
  • Rapid weight loss: >1 kg/week = more muscle loss
  • Too much cardio: Excessive endurance training without resistance

💡 Ideal Fat Loss Protocol: 500 cal deficit + high protein (2g/kg) + strength training 3x/week + adequate sleep = 80-90% fat loss, 10-20% muscle loss (better ratio than typical 75/25).

Realistic Weight Loss Timeline Examples

GoalModerate (0.5kg/wk)Aggressive (0.75kg/wk)Maximum (1kg/wk)
5 kg10 weeks (~2.5 months)6.7 weeks (~1.5 months)5 weeks (~1.2 months)
10 kg20 weeks (~5 months)13.3 weeks (~3 months)10 weeks (~2.5 months)
15 kg30 weeks (~7.5 months)20 weeks (~5 months)15 weeks (~3.75 months)
20 kg40 weeks (~10 months)26.7 weeks (~6.5 months)20 weeks (~5 months)

💡 Remember: These are estimates. Actual results vary based on consistency, metabolism, starting weight, and adherence to the plan.

Frequently Asked Questions

1. How much weight can I lose in a week safely?

Safe, sustainable weight loss is 0.5-1 kg per week (1-2 lbs). This rate preserves muscle, maintains metabolism, and is sustainable long-term.

Weight Loss Rate Guide:

0.25-0.5 kg/week: Very safeExcellent
0.5-1 kg/week: SafeRecommended
1-1.5 kg/week: AggressiveShort-term only
>1.5 kg/week: Too fastUnhealthy

2. How many calories should I eat to lose weight?

Calculate your TDEE (Total Daily Energy Expenditure) and subtract 300-500 calories for moderate weight loss. Never go below 1,500 cal (men) or 1,200 cal (women).

Simple Formula:

1️⃣ Calculate BMR (use calculator above)

2️⃣ Multiply by activity level = TDEE

3️⃣ Subtract 500 calories = Weight loss calories

Example: TDEE = 2,200 cal → Eat 1,700 cal/day → Lose 0.5 kg/week

3. Why am I not losing weight even with calorie deficit?

If you're not losing weight despite being in a deficit, you might be experiencing water retention, metabolic adaptation, or tracking errors.

Common Reasons:

1. Water Retention (Most Common)

  • High sodium intake
  • New exercise routine (muscle inflammation)
  • Menstrual cycle (women)
  • Stress hormones (cortisol)

2. Tracking Errors

  • Underestimating portions
  • Not tracking oils, sauces, drinks
  • Weekend overeating
  • Overestimating exercise calories

3. Metabolic Adaptation

  • Body adapts to lower calories
  • NEAT (Non-Exercise Activity) decreases
  • Solution: Take diet break (eat at maintenance 1-2 weeks)