How many times has the U.S. Constitution been amended?

The U.S. Constitution has been amended a total of 27 times since it was ratified in 1788. The process for amending the Constitution is outlined in Article V, which provides two methods for proposing amendments: by a two-thirds vote in both houses of Congress or by a convention called by two-thirds of the state legislatures. Additionally, amendments must be ratified by three-fourths of the states, either by their legislatures or by conventions within the states. The first ten amendments, known as the Bill of Rights, were ratified in 1791, and subsequent amendments have addressed various issues, including civil rights and the electoral process.

This answer reflects the accepted and historical documentation of the Constitution's amendments, making 27 the correct and definitive count.