List of amendments to the United States Constitution

This page is a list of the amendments to the United States Constitution. Since the Constitution went into effect on March 4, 1789, twenty-seven amendments have been added to the Constitution. This page gives just a short summary of each of these amendments. For more information about each amendment, click on the links in the box at the right of this page. The amendments are numbered in Roman numerals from I (One) to XXVII (Twenty-seven).
Background.
Usually, for an amendment to be approved and added to the Constitution, there are two steps: 
Once this happens, the amendment becomes part of the Constitution.
The first ten amendments to the Constitution were all approved together. As a group, they are called the Bill of Rights.
Unratified amendments.
Between 1789 and December 2014, about 11,623 amendments were proposed in Congress. However, most of these suggested amendments "die" in the committees that suggest them. In total, in the past 227 years, Congress has sent only 33 amendments to the states for ratification just about one out of every 500 suggested amendments. Of these 33, the states have set 27. 
Out of the six unratified amendments, two failed when they were not ratified by a set deadline. The other four are still officially "pending"; they do not have enough votes to pass or fail, but they also do not have deadlines written into them.
Ratified amendments.
The Bill of Rights (Amendments IX).
Congress sent twelve amendments to the states for ratification on September 25, 1789. Ten of these were officially ratified on December 15, 1791: two years, two months, and 20 days after Congress proposed them. Here is a summary of what those amendments say.