Calorie Deficit Calculator
Enter your maintenance calories and target pace to get the exact daily calorie target you need to lose weight — without losing muscle.
Don't know your TDEE? Use our TDEE calculator.
What is a calorie deficit?
A calorie deficit occurs when you consistently consume fewer calories than your body burns (your TDEE). Your body makes up the shortfall by burning stored fat, which is how weight loss happens. A deficit of 500 kcal/day produces roughly 0.45 kg (1 lb) of fat loss per week — a rate most nutrition researchers consider both safe and sustainable.
How large should your deficit be?
A deficit of 300–500 kcal/day is the sweet spot for most people. It's large enough to produce visible results week over week, but small enough that energy, muscle mass, and performance remain largely intact. Deficits above 750 kcal/day increase the risk of muscle loss, hormonal disruption, and rebound eating — making the weight harder to keep off long term.
Deficit + protein = sustainable fat loss
The most reliable strategy for fat loss is a moderate calorie deficit combined with high protein intake. Protein keeps you full, preserves lean muscle, and has a higher thermic effect than carbs or fat (meaning your body burns more calories digesting it). Use the macro calculator to set your protein target alongside your deficit.
Why most people fail at calorie deficits
The number-one reason is inaccurate tracking. Studies show people underestimate their calorie intake by 30–50% on average. Portion sizes are the main culprit — a meal that looks like 400 calories can easily be 700. iCalorie analyses your meal from a single photo, gives you an accurate calorie count in seconds, and lets you adjust the portion size until it matches what you actually ate.
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The easiest way to stay in your deficit
iCalorie logs your meals from a photo in seconds and tells you exactly where you stand. No guessing. No spreadsheets.
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