Weight loss date calculator
If you hold a steady calorie deficit, you can estimate the date you reach your goal weight. One kilogram of body fat stores roughly 7,700 calories, so a 500-calorie daily deficit loses about half a kilogram a week. FitCalcs turns your current weight, target weight and chosen deficit into an estimated finish date. It is a straight-line model, so loss slows as you get lighter: treat the date as a best case and re-check it. This is general information, not personalised dietary advice.
How this is worked out
One kilogram of body fat stores roughly 7,700 kcal, so the time to lose a given amount is the total energy gap divided by your daily deficit:
weeks = (weight to lose kg x 7700) ÷ (daily deficit x 7)
This is a straight-line model. In reality weight loss slows as you get lighter, because a smaller body burns fewer calories, so treat the date as a best case and re-check your numbers every few weeks. The NHS suggests a steady 0.5 to 1 kg a week as safe and sustainable.
Informational only, not medical or dietary advice. Editorially reviewed by FitCalcs, with each figure citing its source.
Calculators and Data Desk, FitCalcs
FitCalcs' editorial desk builds and documents the calculators, citing the underlying equation and the UK dataset behind every number. Health-related tools are editorially reviewed, with figures cited to named UK sources.
Last reviewed: 12 June 2026