Calorie Deficit Calculator
Calculate how long it will take to reach your goal weight. Get your daily calorie target and projected timeline.
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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.
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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
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.
Automatic Calorie Tracking
This calculator gives you a target. Arvo tracks your actual progress, adjusts your calories based on results, and helps you stay on track with personalized coaching.
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