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Calorie Deficit Calculator

Free calorie deficit calculator shows how many calories to eat each day to lose weight at your chosen pace, based on your TDEE and a safe weekly deficit.

Weight loss happens when you consistently eat fewer calories than your body burns, and that gap is the calorie deficit. The safest approach is a moderate deficit of about 0.25-0.75 kg per week, which preserves muscle and is easier to sustain.

This calculator estimates your maintenance calories (TDEE) with the Mifflin-St Jeor equation, subtracts a daily deficit matched to your weekly goal, and never drops your target below your BMR, the energy needed at complete rest.

30 years
1880
175 cm
120220
80 kg
30200
Example
Example: 0.5 kg per Week (Male, 30, 175 cm, 80 kg, Moderate Activity)

BMR = 10 x 80 + 6.25 x 175 - 5 x 30 + 5 = 1,749 kcal
TDEE = 1,749 x 1.55 = 2,711 kcal
Daily deficit = 0.5 x 7,700 / 7 = 550 kcal
Target = 2,711 - 550 = 2,161 kcal
Weekly deficit = 3,850 kcal

Key Insight: 550 kcal/day is a classic moderate deficit, about 0.5 kg per week, without going below BMR.

Frequently Asked Questions

What is a calorie deficit?

It is the difference between the calories you eat and the calories you burn. When you consistently eat less than your body uses, it draws on stored fat for energy and you lose weight.

How big should my deficit be?

0.25-0.75 kg per week is the recommended safe pace (NHLBI). Larger deficits increase muscle loss, fatigue and metabolic adaptation, and are harder to sustain.

Why 7,700 kcal per kg?

It is the classic conversion (about 3,500 kcal per pound) from Wishnofsky 1958. Hall 2008 shows the real requirement changes with body weight, so treat the result as an estimate.

Will a bigger deficit make me lose faster?

Short term yes, but with more muscle loss, fatigue and a stronger drop in metabolism. A sustainable deficit usually gives better long-term results.

Why is my target capped at my BMR?

BMR is the minimum energy for vital functions at rest. Eating below it is hard to sustain and potentially unsafe, so the calculator floors your target there.

Do I need to count calories forever?

No. Use the tool for awareness, re-calculate as your weight changes, and focus on sustainable eating and movement habits.

Estimates are for education only and are not medical advice. A deficit below your BMR increases muscle loss and fatigue risk. Metabolic adaptation lowers TDEE as you lose weight, so re-calculate every 4-6 weeks. Consult a professional for medical conditions.

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