What is the cut-off age for president of the U S?

There is no maximum age limit for the President written in the Constitution. The only age requirement for the Presidency is set forth in Article II, Section I of the Constitution, which mandates that the President be at least 35 years old. However, if the President is unable to discharge the powers and duties of the office (possibly due to age), then Congress can remove the President from office and the Vice President will take over. Age has yet to be a factor in American history as Ronald Reagan was the oldest president; at the end of his term in 1988, he was nearly 77.