How Many Times Has the Constitution Been Amended?

The United States Constitution has been amended 27 times since it took effect in 1789. The first ten of those changes were ratified together in 1791 as the Bill of Rights, and the remaining 17 were adopted one at a time over the next two centuries. The most recent, the 27th Amendment, was ratified in 1992.¹

That count is small on purpose. Article V of the Constitution requires a two-thirds vote in both chambers of Congress to propose an amendment and ratification by three-fourths of the states (38 of 50) to adopt it. More than 11,000 amendments have been introduced in Congress across American history; only 33 ever cleared Congress, and 27 of those were ratified by the states.¹²

The First Ten: The Bill of Rights

The Bill of Rights was ratified on December 15, 1791, after several states refused to support the original Constitution without explicit guarantees of individual liberty. Congress had sent 12 proposed amendments to the states; ten were ratified.³

These ten amendments protect speech, religious exercise, the press, peaceful assembly, and the right to bear arms. They set ground rules for criminal proceedings, including protection against unreasonable searches, the right against self-incrimination, the right to a jury trial, and a ban on cruel and unusual punishment. The Tenth Amendment reserves all powers not specifically granted to the federal government to the states or the people.⁴

The 17 Amendments That Followed

Every amendment after the tenth was ratified individually. Grouped by what they do, the pattern of change becomes clearer.

Ending Slavery and Guaranteeing Equal Protection

Three amendments ratified during Reconstruction reshaped the country. The 13th Amendment (1865) abolished slavery.⁵ The 14th Amendment (1868) granted citizenship to all persons born or naturalized in the United States and barred states from denying anyone equal protection of the laws or depriving anyone of life, liberty, or property without due process. Those clauses have been the basis for rulings on everything from school segregation to marriage equality.⁶ The 15th Amendment (1870) prohibited denying the right to vote based on race, color, or previous condition of servitude, though many states circumvented it for nearly a century.⁷

Expanding the Right to Vote

Voting rights are the single biggest theme running through the amendments. Beyond the 15th, four more broadened who could vote:

19th Amendment (1920) prohibited denying the vote based on sex, securing women’s suffrage nationwide.⁸
23rd Amendment (1961) gave residents of Washington, D.C., electors in presidential elections.
24th Amendment (1964) banned poll taxes in federal elections.⁹
26th Amendment (1971) lowered the voting age from 21 to 18, driven by the argument that draft-age Americans should be able to vote on the leaders sending them to war.¹⁰

The National Archives notes that 17 of the 27 ratified amendments secure or expand individual rights, including voting rights.¹

Changing How the Government Works

Other amendments restructured federal offices. The 12th Amendment (1804) fixed a flaw in the original presidential election system by requiring electors to cast separate ballots for president and vice president, a change prompted by the tied 1800 election between Thomas Jefferson and Aaron Burr.¹¹ The 17th Amendment (1913) moved the election of U.S. senators from state legislatures to a direct popular vote.¹² The 20th Amendment (1933) moved Inauguration Day from March to January, shortening the lame-duck period. The 22nd Amendment (1951) capped presidents at two terms. The 25th Amendment (1967) created a formal process for transferring power when a president cannot serve.

Taxes, Prohibition, and the 11th

The 11th Amendment (1795) came first after the Bill of Rights, limiting the ability of individuals to sue states in federal court and establishing the principle of state sovereign immunity.¹³ The 16th Amendment (1913) gave Congress explicit power to collect income taxes without dividing the revenue among states by population, overturning an 1895 Supreme Court decision and laying the foundation for the modern federal tax system.¹⁴

The 18th Amendment (1920) banned the manufacture, sale, and transportation of alcohol nationwide. It was repealed just 13 years later by the 21st Amendment (1933), the only amendment that exists solely to undo a previous one.¹⁵

The 27th Amendment: The Most Recent

The 27th Amendment prevents members of Congress from giving themselves a pay raise that takes effect before the next election of Representatives. It was originally proposed in 1789 alongside what became the Bill of Rights, then sat for two centuries until a college student’s research paper in 1982 sparked a grassroots ratification campaign. It was ratified on May 7, 1992, more than 202 years after Congress first sent it to the states, the longest ratification period in American history.¹⁶

Because Congress set no ratification deadline on that proposal, it never expired. No amendment has been ratified since.¹⁷

A Note on the Equal Rights Amendment

Readers sometimes ask whether the count should be higher because of the Equal Rights Amendment. It is not part of the Constitution. Congress passed the ERA in 1972 with a ratification deadline that was later extended to 1982; only 35 states had ratified by then. Nevada ratified in 2017, Illinois in 2018, and Virginia in 2020, bringing the paper total to 38, but the National Archivist has stated the ERA cannot be certified because the deadline has expired. The Department of Justice’s Office of Legal Counsel has twice affirmed that position, and federal courts have agreed.¹⁸

Why the Number Stays Small

Getting two-thirds of both chambers of Congress to agree on constitutional text is hard on its own. Then 38 state legislatures, each with their own politics, have to sign on. That double supermajority requirement means an amendment needs broad, sustained support across regions and parties. The framers designed the process this way deliberately, wanting a Constitution that could be changed but not easily changed. More than three decades have now passed without a ratification, and the total sits at 27.²

1
National Archives. Amending America
2
Congress.gov. ArtV.1 Overview of Article V, Amending the Constitution
3
National Archives. The Bill of Rights: How Did it Happen – Section: Ratifying the Bill of Rights
4
National Archives. The Bill of Rights: A Transcription
5
Congress.gov. U.S. Constitution – Thirteenth Amendment
6
Congress.gov. U.S. Constitution – Fourteenth Amendment
7
Congress.gov. U.S. Constitution – Fifteenth Amendment
8
National Archives. 19th Amendment to the U.S. Constitution: Women’s Right to Vote (1920)
9
National Constitution Center. 24th Amendment – Abolition of Poll Taxes
10
Ronald Reagan Presidential Library and Museum. Constitutional Amendments – Amendment 26 – Voting at the Age of Eighteen
11
Ronald Reagan Presidential Library and Museum. Constitutional Amendments – Amendment 12 – Electing the President and Vice President
12
National Archives. 17th Amendment to the U.S. Constitution: Direct Election of U.S. Senators (1913)
13
Congress.gov. General Scope of State Sovereign Immunity
14
Ronald Reagan Presidential Library and Museum. Constitutional Amendments – Amendment 16 – Income Taxes
15
Congress.gov. Constitution Annotated – Twenty-First Amendment
16
Congress.gov. Amdt27.2.5 Ratification of the Twenty-Seventh Amendment
17
Congress.gov. Congressional Deadlines for Ratification of an Amendment
18
National Archives. Statement on the Equal Rights Amendment Ratification Process