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Calorie Deficit Calculator
Plan your daily calorie deficit to reach your target weight
Nutrition
kg
kg
weeks
What This Calculator Measures
This calculator determines the daily caloric deficit required to lose a specific amount of weight over your chosen timeframe. It helps you set realistic expectations and avoid crash dieting.
How It Works
The calculation is based on the established estimate that 1 kg of body fat contains approximately **7,700 kcal** of stored energy:
**Daily Deficit = (Weight to Lose x 7,700) / (Weeks x 7)**
For example, losing 10 kg in 16 weeks requires: (10 x 7,700) / (16 x 7) = **688 kcal/day deficit**.
| Daily Deficit | Weekly Loss | Sustainability |
|---|---|---|
| 300-500 kcal | 0.3-0.5 kg | Conservative, best for muscle retention |
| 500-750 kcal | 0.5-0.75 kg | Moderate, sustainable for most |
| 750-1000 kcal | 0.75-1.0 kg | Aggressive, monitor recovery |
| 1000+ kcal | 1.0+ kg | Too aggressive, high muscle loss risk |
Recommendations
•A deficit of 500 kcal/day (roughly 0.5 kg/week loss) is considered the gold standard for sustainable fat loss while preserving muscle.
•Deficits above 750 kcal/day are generally not recommended for resistance-trained individuals because the risk of muscle loss and performance decline increases sharply.
•If the calculator shows a deficit over 1000 kcal/day, extend your timeline rather than crash dieting.
Limitations
•Real-world weight loss is not perfectly linear. Water retention, glycogen fluctuations, and hormonal cycles cause weight to fluctuate day-to-day.
•The 7,700 kcal per kg figure is an average. Some of the weight lost will be water and lean tissue, not pure fat.
•Metabolic adaptation means your TDEE decreases as you lose weight, which can slow progress over time.
Frequently Asked Questions
- What calorie deficit should I aim for to lose fat?
- A 300-500 calorie daily deficit is the sweet spot. That's about 0.5-1 lb of fat loss per week. Bigger deficits (700+) cause more muscle loss, worse workouts, and are harder to sustain. Slow and steady wins the fat loss race.
- How long does it take to see results from a calorie deficit?
- You'll notice scale changes in 1-2 weeks and visible changes in the mirror after 4-6 weeks. At 500 calories under maintenance, expect about 4-5 lbs of fat loss per month. That adds up fast -- 12-15 lbs in 3 months is a big visual difference.
- Will I lose muscle in a calorie deficit?
- You will lose some if you don't lift and eat enough protein. Keep training heavy (don't switch to light weights and high reps), eat 1g of protein per pound of bodyweight, and keep the deficit moderate. That's the formula for preserving muscle while losing fat.
- Should I eat back the calories I burn during exercise?
- No. Your TDEE estimate already accounts for your activity level. Eating back exercise calories is the number one reason people don't lose weight on a "deficit." Stick to your calorie target regardless of what your watch says you burned.