How many kilometers to walk to lose 1kg in a week?

How exactly does one calculate the number of kilometers one needs to walk in order to lose 1kg in a week? Is there a specific formula or method that takes into account factors such as weight, height, age, and activity level? And how does the duration and intensity of the walks play into this equation? Could you provide some insight into the science behind this question and how it relates to achieving weight loss goals?