Caloric Deficit Calculator
Find the exact caloric deficit to reach your goal weight in your target timeframe — without losing muscle or crashing your metabolism. Based on energy balance principles.
Your Numbers
Use the TDEE calculator if unknown.
The calories you plan to eat each day.
Your Result
Enter your current weight, goal weight, and TDEE to calculate your optimal deficit.
📋 What Your Result Means
For educational purposes only — not medical advice.
A moderate deficit of around 500 kcal/day is generally the sweet spot -- aggressive enough to produce visible results (roughly 0.5 kg/week) but moderate enough to preserve muscle and avoid metabolic adaptation. For evidence-based safety, aim to lose 0.5-1% of your body weight per week. Faster rates increase muscle loss and hormonal disruption, particularly in lean individuals (Helms et al. 2014, DOI: 10.1186/2193-1801-3-661).
Metabolic adaptation will fight you. Your body reduces energy expenditure during sustained dieting — not just from weighing less, but through hormonal downregulation of metabolism. The MATADOR study showed that intermittent dieting (2 weeks deficit, 2 weeks maintenance) preserved metabolic rate significantly better than continuous dieting over the same total deficit period (Byrne et al. 2018, DOI: 10.1038/ijo.2017.206). Consider planned diet breaks every 4-8 weeks.
Resistance training is non-negotiable during a deficit. Without it, up to 25% of weight lost can come from lean tissue. With consistent resistance training and adequate protein (2.0-2.4 g/kg), you can preserve nearly all muscle mass even in a significant deficit.
Recalculate every 4 weeks. As you lose weight, your TDEE drops. A deficit that produced 0.5 kg/week loss at 90 kg will produce less at 80 kg unless you adjust intake or increase activity.
Required deficit = (fat_kg × 7700 kcal) ÷ timeframe_days
Daily intake = TDEE − daily deficit
Limitations
Fat loss is not linear — metabolic adaptation reduces TDEE as weight decreases beyond what body mass change alone would predict. Recalculate every 4 weeks as you lose weight. The 7,700 kcal/kg fat figure is an approximation; individual variation exists based on body composition and metabolic efficiency. Diet breaks (2 weeks at maintenance every 4-8 weeks) may attenuate metabolic adaptation.
✓ Strong EvidenceWant to learn more? Read our in-depth article: How Big Should Your Caloric Deficit Be for Fat Loss? →
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