Calorie Deficit Calculator

The formula proceeds in three steps. Step 1: compute the weekly calorie deficit required for the target weight loss — weekly deficit = target kg × 7,700 kcal. Step 2: convert to a daily figure by dividing by 7. Step 3: subtract the daily deficit from TDEE — daily calorie target = TDEE − (weekly deficit ÷ 7). Worked example: TDEE of 2,500 kcal/day, target loss of 0.5 kg/week. Weekly deficit = 0.5 × 7,700 = 3,850 kcal. Daily deficit = 3,850 ÷ 7 = 550 kcal. Daily calorie target = 2,500 − 550 = 1,950 kcal/day. The 7,700 kcal/kg figure is the most widely cited estimate of the energy content of one kilogram of human adipose tissue. The actual value ranges from approximately 7,400–7,900 kcal/kg depending on body composition and hydration status, so real-world fat loss varies slightly from the mathematical prediction. The 1,000 kcal/day floor flags targets falling below a clinically recognized safety threshold; most practitioners set this floor higher at 1,200–1,500 kcal/day depending on body size, but 1,000 kcal represents the minimum used in medically supervised programs.