Weight Loss Calculator
Work out a safe calorie deficit and a realistic timeline to your goal weight, using the Mifflin-St Jeor equation and the rule that about 7,700 kcal equals 1 kg of body fat. An estimate — aim for 0.5–1% of body weight per week and never go below the safety floors.
Your weight-loss plan
22.0 weeks to goal
Lose 10.0 kg at about 0.45 kg/week (0.53% of body weight per week) by eating 1,700 kcal/day.
| Daily calorie target | 1,700 kcal/day |
| Expected loss rate | 0.45 kg/week |
| Total to lose | 10.0 kg |
| Estimated time to goal | 22.0 weeks (5.1 months) |
Safety floors: never aim below 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision.
Formula & source — 7,700 kcal ≈ 1 kg of body fat
Weekly loss = (daily deficit × 7) ÷ 7,700 kcal/kg. Time to goal = (current weight − goal weight) ÷ weekly loss. The 7,700 kcal/kg figure is the widely used energy equivalent of a kilogram of body fat; real loss slows over time as the body adapts (Hall et al., The Lancet, 2011), so treat the timeline as a rough guide.
Estimate, not medical advice. FitCalc results are estimates based on population-average formulas. They are not a diagnosis, a prescription, or a substitute for professional medical advice. If you have a medical condition, are pregnant, or take medication, talk to a doctor or registered dietitian before changing your diet or exercise. FitCalc claims no medical credentials.
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