Deficit & Surplus Calculator - Calorie Targets & Weight Projection | SatisFIT

Deficit & Surplus Calculator

Find the right calorie target and see how your weight will change over time

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Daily Deficit-500 kcal / day
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What's next?

Your deficit or surplus is the starting point - consistency over weeks is what drives results. SatisFIT tracks every workout so you can stay on course and adjust when needed. Try SatisFIT free

How it works

This calculator estimates your TDEE (Total Daily Energy Expenditure) using the Mifflin-St Jeor equation, then applies your chosen deficit or surplus to calculate a daily calorie target. The weight projection chart shows how your weight changes over 24 weeks, accounting for the fact that your TDEE decreases as you lose weight (or increases as you gain). This gives you a more realistic picture than simple linear projections. For a detailed TDEE breakdown, use the Total Daily Energy Expenditure (TDEE) Calculator.

Choosing the right deficit

200–300 kcal: Conservative approach. Slow fat loss with minimal impact on energy and performance. Ideal for lean individuals or those already close to their goal weight.

400–500 kcal: The sweet spot for most people. Sustainable rate of 0.3–0.5 kg/week with manageable hunger and good muscle preservation when combined with strength training.

600–750 kcal: Moderate-aggressive. Faster results but requires careful attention to protein intake and training to minimize muscle loss.

1000+ kcal: Aggressive deficit. Only recommended for significantly overweight individuals or under professional guidance. High risk of muscle loss and metabolic adaptation.

Choosing the right surplus

100–200 kcal: Lean bulk. Minimizes fat gain, suitable for intermediate and advanced lifters who gain muscle slowly.

200–300 kcal: The standard recommendation for most lifters. Provides enough energy for muscle growth without excessive fat accumulation.

400–500 kcal: More aggressive surplus. Can be useful for beginners who have higher muscle-building potential, or for those who struggle to gain weight.

Why weight loss slows down

As you lose weight, your body burns fewer calories at rest (lower BMR) and during activity (lower TDEE). This means the same calorie intake that created a 500 kcal deficit at 90 kg might only create a 350 kcal deficit at 80 kg. The projection chart above accounts for this by recalculating your TDEE at each new weight. This is why weight loss plateaus are common and why periodic recalculation is important.

Frequently asked questions

How big should my calorie deficit be?

A deficit of 400–500 kcal per day is recommended for sustainable fat loss while preserving muscle. This translates to roughly 0.3–0.5 kg of weight loss per week. Larger deficits speed up weight loss but increase the risk of muscle loss and metabolic adaptation.

Why does weight loss slow down over time?

As you lose weight, your body burns fewer calories (lower TDEE). This means the same calorie intake creates a smaller deficit over time. The projection chart accounts for this by recalculating TDEE at each new weight. To maintain the same rate of loss, you need to either reduce intake further or increase activity.

How much surplus do I need to build muscle?

A surplus of 200–300 kcal per day is sufficient for most people to maximize muscle growth while minimizing fat gain. Beginners may benefit from slightly larger surpluses (300–400 kcal) due to faster potential muscle growth. Going beyond 500 kcal rarely leads to additional muscle - just more fat.

How accurate is the weight projection?

The projection is based on the thermodynamic model (~7,700 kcal per kg of body fat) and accounts for TDEE decreasing as weight drops. Real-world results may vary due to water retention, metabolic adaptation, and changes in activity level. Treat it as a realistic estimate and adjust based on actual progress.