Calorie Deficit Calculator
Calculate how long it will take to reach your goal weight. Get your daily calorie target and projected timeline.
How much calorie deficit to lose 0.5kg per week?
To lose 0.5kg/week, create a 500 calorie daily deficit (3,500 cal/week). For 1kg/week, you need a 1,000 cal/day deficit. The deficit is calculated by subtracting your target calories from your TDEE (total daily energy expenditure).
Calculate Your Timeline
Enter your details to see your weight change timeline
Calculate how long it will take to reach your goal weight
About Calorie Deficits
1 kg of body fat contains approximately 7,700 calories. To lose 0.5 kg per week, you need a daily deficit of about 550 calories.
Safe rate of loss: 0.5-1% of body weight per week. Faster rates may lead to muscle loss, metabolic adaptation, and nutrient deficiencies.
Minimum calories: Women shouldn't go below 1,200 kcal/day and men below 1,500 kcal/day without medical supervision.
Note: These are estimates. Real-world weight loss varies due to water retention, muscle changes, and metabolic adaptation. Weigh yourself weekly and adjust calories based on actual progress.
Related Tools
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- Automatic progress tracking
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- Personalized coaching
Want to Learn More?
Dive deeper into the science of fat loss and nutrition with our comprehensive guides.
The Calorie Deficit Formula
Understanding the math behind weight loss helps you set realistic expectations:
Where TDEE (Total Daily Energy Expenditure) is the total calories your body burns per day, and Deficit is the calorie reduction needed to lose weight.
This is the energy stored in 1kg of adipose tissue
7,700 ÷ 14 days = 550 calories per day
Safe middle ground for most people
More aggressive, requires discipline
Example Calculation
Your TDEE is 2,400 calories and you want to lose 0.5kg per week:
- 1Required deficit: 7,700 ÷ 14 = 550 calories/day
- 2Daily target: 2,400 − 550 = 1,850 calories/day
- 3Weekly deficit: 550 × 7 = 3,850 calories/week
Practical Examples: Your Weight Loss Timeline
Here's how long different weight loss goals typically take with a sustainable approach:
Lose 5kg
10-20 weeks (0.25-0.5 kg/week)
7-10 weeks (0.5-0.75 kg/week)
Great for small adjustments or maintaining muscle while cutting
Lose 10kg
20-40 weeks (5-10 months)
14-20 weeks (3.5-5 months)
Include 1-2 diet breaks for better adherence
Lose 15kg
30-60 weeks (7-15 months)
20-30 weeks (5-7.5 months)
Plan for 2-3 maintenance phases to prevent metabolic adaptation
Lose 20kg+
40-80 weeks (10-20 months)
27-40 weeks (6.5-10 months)
Lifestyle change mindset - this is a marathon, not a sprint
💡 These timelines assume consistent adherence. Real progress includes plateaus, social events, and life happening. Add 20-30% buffer time for realistic expectations.
Recommended Calorie Deficits by Body Type
Your ideal deficit depends on how much fat you have to lose. Leaner individuals need smaller deficits to preserve muscle:
| Body Fat % | Recommended Deficit | % of TDEE | Notes |
|---|---|---|---|
| Men >25% / Women >35% | 750-1000 cal | 25-30% | Higher body fat = larger safe deficit |
| Men 20-25% / Women 28-35% | 500-750 cal | 20-25% | Moderate deficit, good balance |
| Men 15-20% / Women 22-28% | 400-500 cal | 15-20% | Slower loss, better muscle retention |
| Men 12-15% / Women 18-22% | 300-400 cal | 10-15% | Minimize muscle loss priority |
| Men <12% / Women <18% | 200-300 cal | 5-10% | Very slow cuts, competition prep |
⚠️ Never go below 1,200 calories/day (women) or 1,500 calories/day (men) without medical supervision. Extreme deficits cause muscle loss, hormonal issues, and nutrient deficiencies.
Understanding Calorie Deficits
A calorie deficit occurs when you consume fewer calories than your body burns. This forces your body to use stored energy (fat) for fuel, resulting in weight loss.
The size of your deficit determines how quickly you lose weight. A larger deficit means faster weight loss, but also increases the risk of muscle loss, fatigue, and metabolic adaptation.
Recommended Rates of Weight Loss
The optimal rate depends on your starting point and goals:
| Rate | Type | Best For |
|---|---|---|
| 0.25-0.5 kg/week | Conservative | Best for those with less to lose, athletes, or those prioritizing muscle retention |
| 0.5-0.75 kg/week | Moderate | Good balance of speed and sustainability for most people |
| 0.75-1 kg/week | Aggressive | Suitable for those with significant weight to lose, requires discipline |
| >1 kg/week | Not recommended | High risk of muscle loss, metabolic adaptation, and nutrient deficiencies |
The Science Behind Weight Loss
Energy Balance
Weight loss is fundamentally about energy balance. 1 kg of body fat contains approximately 7,700 calories of stored energy.
Metabolic Adaptation
As you lose weight, your body adapts by burning fewer calories. This is why weight loss often slows down over time.
Non-Linear Progress
Weight loss isn't linear. Water retention, hormones, and digestive contents cause daily fluctuations of 1-2 kg.
Muscle Matters
Muscle burns more calories at rest. Preserving muscle through protein intake and resistance training keeps your metabolism higher.
Tips for Successful Weight Loss
- Track your food intake accurately using a food scale and calorie tracking app
- Weigh yourself at the same time each day (morning, after bathroom) and look at weekly averages
- Prioritize protein (1.6-2.2g per kg of body weight) to preserve muscle
- Strength train 2-4 times per week to maintain muscle mass
- Get 7-9 hours of quality sleep per night
- Include diet breaks (1-2 weeks at maintenance) every 8-12 weeks for long diets
Common Calorie Deficit Myths Debunked
❌ Cutting more calories means faster fat loss
✅ Extreme deficits cause muscle loss and metabolic adaptation. A moderate deficit (300-750 cal) preserves muscle and is more sustainable.
❌ Your metabolism slows down permanently in a deficit
✅ Metabolic adaptation is modest (5-15%) and reversible. NEAT (daily activity) drops more than metabolism itself. Both return to normal when eating resumes.
❌ You must eliminate carbs to lose fat
✅ No macronutrient must be eliminated. Caloric deficit is what matters for fat loss. Carbs support training performance and can be part of any successful diet.
❌ Eating at night makes you gain weight
✅ Meal timing doesn't affect fat loss - total daily calories do. Late eating only matters if it leads to overeating.
❌ You can target where you lose fat
✅ Spot reduction doesn't exist. Fat loss occurs systemically based on genetics. You can't choose to lose belly fat first.
Frequently Asked Questions
How do I calculate my calorie deficit?
To calculate your calorie deficit: (1) Determine your TDEE (Total Daily Energy Expenditure), (2) Subtract 300-750 calories depending on your desired rate of loss, (3) The result is your daily calorie target for weight loss. Our calculator does this automatically.
How long will it take to lose weight?
The time depends on how much weight you want to lose and your rate of loss. A safe rate is 0.5-1% of body weight per week. For example, losing 10kg at 0.5kg/week takes about 20 weeks (5 months).
What is a safe calorie deficit?
A safe deficit is typically 300-750 calories below your TDEE. This results in 0.25-0.75 kg (0.5-1.5 lb) of weight loss per week. Going below 1200 calories/day for women or 1500 for men is not recommended without medical supervision.
Will I lose muscle on a calorie deficit?
You can minimize muscle loss by: (1) Keeping your deficit moderate (not extreme), (2) Eating adequate protein (1.6-2.2g per kg of body weight), (3) Strength training regularly, (4) Getting enough sleep.
How accurate is this calculator?
The calculator provides estimates based on established formulas. Real-world results vary due to metabolic adaptation, water weight fluctuations, and individual differences. Track your weight weekly and adjust calories based on actual progress.
What is TDEE and why do I need it?
TDEE (Total Daily Energy Expenditure) is the total number of calories you burn per day. To lose weight, you need to eat fewer calories than your TDEE. Use our TDEE calculator to find yours.
How many calories are in 1kg of body fat?
One kilogram of body fat contains approximately 7,700 calories (or about 3,500 calories per pound). This means to lose 1kg per week, you need a daily deficit of about 1,100 calories. For 0.5kg per week, you need a 550 calorie daily deficit.
Should I eat back exercise calories?
It depends on your goals. For weight loss, avoid eating back all exercise calories as trackers often overestimate burn. A conservative approach is to eat back 50% of tracked exercise calories. If losing weight too fast or feeling fatigued, eat back more.
Why has my weight loss stalled?
Plateaus happen for several reasons: (1) Metabolic adaptation - your body burns fewer calories as you lose weight, (2) Increased water retention, (3) Underestimating food intake. To break through: recalculate your TDEE at your new weight, take a 1-2 week diet break, or increase activity.
Is 1,200 calories too low?
For most people, 1,200 calories is too low and can lead to nutrient deficiencies, muscle loss, and metabolic slowdown. Women should generally not go below 1,200 cal/day and men below 1,500 cal/day without medical supervision. A moderate deficit is more sustainable long-term.
Automatic Calorie Tracking
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