Weight Loss Target Date Calculator
Sustainable weight loss comes from a consistent calorie deficit. A deficit of about 500 kcal/day yields roughly 0.5 kg per week, since a kilogram of body fat stores around 7,700 kcal. This calculator turns a deficit into a timeline.
Enter your current weight, target weight, and daily calorie deficit. The calculator returns the estimated days to your goal and the implied weekly loss.
It turns a daily calorie deficit into a concrete timeline, so you can see whether your target date is realistic or whether the deficit needs adjusting.
Enter your values to see the result.
How this is calculated
Sustainable weight loss comes from a consistent calorie deficit. This calculator estimates the timeline from the energy content of body fat: roughly 7,700 kcal per kilogram. It first finds the total energy to lose as (current weight − target weight) × 7,700, then divides that by the daily calorie deficit to get the days to the goal. The implied weekly loss is the deficit times seven, divided by 7,700.
A deficit of about 500 kcal/day yields roughly 0.45 kg per week, which is a widely cited sustainable rate. Larger deficits lose faster but increase hunger, muscle loss and rebound risk.
The model assumes a constant deficit and a constant energy cost per kilogram. It does not capture adaptive thermogenesis (metabolism slowing as you lose weight, which shrinks the real deficit over time), water-weight shifts early in a diet, muscle loss if protein and resistance training are inadequate, or the fact that the same deficit produces less loss as you get smaller. Recalculate periodically as your weight changes, and treat the timeline as an estimate to adjust by real-world results.
Worked example
Current weight 85 kg, target 75 kg, daily deficit 500 kcal.
- 1Weight to lose = 85 − 75 = 10 kg.
- 2Total energy = 10 × 7,700 = 77,000 kcal.
- 3Days to goal = 77,000 ÷ 500 = 154 days (about 22 weeks); weekly loss = 500 × 7 ÷ 7,700 ≈ 0.45 kg/wk.
Frequently asked questions
- How is the timeline calculated?
- Total energy to lose = (current − target) kg × 7,700 kcal/kg. Days = that total ÷ daily deficit. A 500 kcal/day deficit loses about 0.45 kg per week.
- Is a bigger deficit faster and better?
- Faster, but not always better. Very large deficits increase muscle loss, hunger and rebound risk. Most people do best with 300–700 kcal/day.
- Why does weight loss slow over time?
- As you lose weight, your energy needs fall, so the same intake produces a smaller deficit. Recalculate periodically and adjust intake or activity.
- How is the timeline calculated?
- Total energy to lose = (current − target) kg × 7,700 kcal/kg. Days = that total ÷ daily deficit. A 500 kcal/day deficit loses about 0.45 kg per week, a widely cited sustainable rate.
- Why does weight loss slow over time?
- As you lose weight, your energy needs fall, so the same intake produces a smaller deficit. Recalculate periodically and adjust intake or activity to keep the deficit steady as you get smaller.
Related calculators
Method: 7,700 kcal per kg of body fat divided by the daily deficit. No external data source. Last updated: September 2026.
These results are general estimates from established formulas and are not medical advice. They depend on the accuracy of the values you enter and on individual factors the formulas cannot capture. Consult a qualified healthcare professional before making decisions about your diet, training or treatment.