It's actually quite common for one foot to be slightly larger than the other. In fact, studies have shown that up to 60% of people have feet that are different sizes. This difference can be as little as a fraction of an inch, or as much as a full shoe size.
There are a few reasons why this happens. Firstly, our feet are not perfectly symmetrical, just like other parts of our body. Secondly, our feet are subjected to different levels of stress and pressure throughout our daily activities, which can cause them to expand or contract slightly.
Another factor that can contribute to differences in foot size is genetics. Some people may inherit slightly larger or smaller feet from their parents.
While having one foot larger than the other may be a source of frustration when it comes to finding well-fitting shoes, it is generally not a cause for concern or a sign of a serious medical condition.