What is the maximum length of time a president can serve?

The maximum length of time a president can serve is ten years, as stipulated by the 22nd Amendment to the United States Constitution. This amendment, ratified in 1951, limits an individual to two elected terms as president, which totals eight years. However, it also allows for the possibility that if a vice president assumes the presidency (due to the president's death, resignation, or removal) and serves more than two years of that term, they can still be elected for only one additional term. This means that, theoretically, a person could serve a maximum of ten years—two full elected terms plus up to two years as the acting president.