Weight Loss Timeline Calculator
Estimate how long it takes to reach a goal weight from a daily calorie deficit or an athlete-friendly 0.25-1% weekly loss rate, with checkpoint projections and suggested intake.
Results
- Estimated time to goal
- 124 days
- About 17.7 weeks at 500 kcal/day deficit
- Required daily deficit
- 500 kcal
- Your chosen deficit
- Projected weekly loss
- 0.45 kg/week
- 0.57% of bodyweight per week
- Total energy deficit needed
- 61,600 kcal
- 8 kg to lose (7,700 kcal/kg)
Straight-line projection (assumes the deficit is held exactly)
| Checkpoint | Projected weight | Cumulative loss |
|---|---|---|
| Week 4 | 78.2 kg | 1.8 kg |
| Week 8 | 76.4 kg | 3.6 kg |
| Week 12 | 74.5 kg | 5.5 kg |
| Week 16 | 72.7 kg | 7.3 kg |
| Week 20 | 72 kg | 8 kg |
| Week 24 | 72 kg | 8 kg |
Common deficit levels and projected rates
| Daily deficit | Weekly loss | % of 80 kg |
|---|---|---|
| 300 kcal | 0.27 kg/week | 0.34% |
| 500 kcal | 0.45 kg/week | 0.57% |
| 750 kcal | 0.68 kg/week | 0.85% |
| 1000 kcal | 0.91 kg/week | 1.14% |
How it works & limitations
The 7,700 kcal assumption
Weight-loss models approximate 1 kg of fat mass at roughly 7,700 kcal (about 3,500 kcal/lb), based on the energy-equivalence literature. Real-world loss is slower than straight-line math because metabolic rate adapts, water and glycogen shift, and adherence varies.
Sustainable rates for athletes
Aim for 0.5-1% of bodyweight per week (often 0.5-1 kg/week) to preserve lean mass and jump performance. Faster deficits increase muscle loss, hunger and training-quality drops. Recalculate as your maintenance calories fall and as you get lighter. When height is provided, the calculator blocks any current or goal BMI below 18.5.
Why reality differs from the projection
Early weight loss includes water and glycogen; later loss slows as metabolic adaptation and smaller energy needs kick in. Use weekly scale trends (not daily readings), keep protein high, and adjust intake every 2-4 weeks instead of chasing the predicted date.
Sources
Last updated 2026-08-13
- Hall, K. D. (2008). What is the required energy deficit per unit weight loss? International Journal of Obesity, 32(3), 573-576.
- Thomas, D. M., et al. (2014). Time to correctly predict the amount of weight loss with dieting. Journal of the Academy of Nutrition and Dietetics, 114(1), 36-41.
A planning estimate, not a guarantee. Weight loss is non-linear; use weekly scale trends and performance markers to adjust rather than chasing the predicted date. Not appropriate for underweight users (BMI below 18.5).
Frequently asked questions
How many calories are in a kilogram of fat?
Roughly 7,700 kcal per kg (about 3,500 kcal per pound). This is an energy-equivalence approximation; real weight loss changes as metabolic rate adapts and water balance shifts, so treat the timeline as a planning estimate.
How fast should I lose weight?
A sustainable target is about 0.5-1% of bodyweight per week, often 0.5-1 kg/week. Faster loss increases muscle loss and rebound risk, especially for athletes trying to preserve jump performance.