Goal Weight Timeline Calculator

About this calculator

This calculator translates a daily calorie deficit into a timeline: given your current weight, goal weight and how many calories below maintenance you eat each day, it estimates how many days or weeks it will take to get there. It's built on the widely used approximation that roughly 7,700 kcal of cumulative deficit corresponds to one kilogram of body weight lost, so the daily deficit you enter gets converted directly into a rate of weight loss per week.

People starting a diet use it to set a realistic, sustainable target rather than guessing — a very large deficit finishes faster on paper but is harder to maintain and more likely to cost muscle along with fat, while a modest deficit takes longer but is easier to stick to. It's also useful for checking whether a goal date (an event, a trip, a competition) is actually achievable at a safe rate of loss.