Weight Management
Weight Loss Calculator — Timeline & Calorie Deficit
Estimate the time, calorie deficit, and target date for reaching your goal weight.
Your Goal
The Science of Weight Loss
Weight loss occurs when you consistently consume fewer calories than you burn. One kilogram (2.2 lbs) of body fat contains approximately 7,700 calories.
The 7,700 Calorie Rule
Weeks to goal = weight to lose (kg) ÷ weekly loss rate (kg/week)
Daily deficit = (weekly rate × 7,700) ÷ 7 days
Daily deficit = (weekly rate × 7,700) ÷ 7 days
Safe Weight Loss Guidelines (WHO)
- 0.25–0.5 kg/week: Slow, very sustainable — ideal for preserving muscle
- 0.5–1.0 kg/week: Standard rate — well within healthy guidelines
- 1.0 kg/week: Aggressive — requires careful nutrition management
- Over 1 kg/week: Not recommended without medical supervision
⚠️ Important: Never eat below 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision. Extreme deficits cause muscle loss and nutritional deficiencies.
Tips to Stick to Your Deficit
- Track meals with a food diary app (MyFitnessPal, Cronometer)
- Prioritize high-protein foods to stay full and preserve muscle
- Drink 2–3 liters of water daily — see our Water Calculator
- Weigh yourself weekly (same time, same day) for accurate trends