How the deficit is calculated
One kilogram of body fat stores roughly 7,700 kcal (about 3,500 kcal per pound). To lose a given amount of weight in a number of days, we spread that energy across the days: daily deficit = (kg to lose × 7,700) ÷ days. Your target intake is your TDEE minus that daily deficit.
How to use it
Enter your maintenance calories (TDEE), your BMR, how much you want to lose and over how many days. We show your daily target and warn you if the plan is too aggressive or dips below safe limits.
Frequently asked questions
- How big should a calorie deficit be?
- A deficit of 300–500 kcal/day is sustainable for most people, giving roughly 0.3–0.5 kg of fat loss per week.
- Is 1 kg of fat really 7,700 kcal?
- It is the widely used estimate. Real results vary with water, muscle and metabolic changes, so track and adjust.
- What is the lowest I should eat?
- As a guide, not below about 1,200 kcal for women or 1,500 kcal for men without medical supervision.
- Why is fast weight loss discouraged?
- Aggressive deficits cost muscle, slow metabolism and are hard to maintain. A moderate deficit preserves more lean mass.