The World's Constitutions

A constitution is the one document a country writes about itself on purpose. Most of them do not last.

Countries

196

with a constitutional record

Systems since 1789

758

555 already replaced

Median life

14 yrs

555 replaced, mean 15.2

Oldest in force

1789

United States

The oldest still standing

Adoption year of the constitution currently in force.

How this is measured
Just 9 countries are governed by a document written before the First World War, and 16 by one written before the end of the Second.
1
United States
236 years old, 0.68 amendments / decade
1789
2
Netherlands
211 years old, 1.23 amendments / decade
1814
3
Norway
211 years old, — amendments / decade
1814
4
Belgium
194 years old, 1.86 amendments / decade
1831
5
Argentina
172 years old, 0.76 amendments / decade
1853
6
Canada
158 years old, 1.96 amendments / decade
1867
7
Luxembourg
157 years old, 1.59 amendments / decade
1868
8
Tonga
150 years old, — amendments / decade
1875
9
Australia
124 years old, 0.65 amendments / decade
1901
10
Mexico
108 years old, 7.50 amendments / decade
1917
11
Liechtenstein
104 years old, 3.46 amendments / decade
1921
12
Lebanon
99 years old, — amendments / decade
1926

How often a constitution changes

Amendment events per decade in force, for every constitution at least twenty years old.

How this is measured
This is the closest thing to an honest difficulty measure, because it records what actually happened rather than what the amendment clause says. Sort any column. A note on counting: the source records amendment events, not amended articles. The United States shows 16 events for 27 amendments, because the ten articles of the Bill of Rights were ratified as one act.
Afghanistan
0 events · adopted 2004 · last changed 2004
0.00
per decade
Andorra
0 events · adopted 1993 · last changed 1993
0.00
per decade
Antigua & Barbuda
0 events · adopted 1981 · last changed 1981
0.00
per decade
Bahamas
0 events · adopted 1973 · last changed 1973
0.00
per decade
Denmark
0 events · adopted 1953 · last changed 1953
0.00
per decade
East Timor
0 events · adopted 2002 · last changed 2002
0.00
per decade
Eritrea
0 events · adopted 1997 · last changed 1997
0.00
per decade
Eswatini
0 events · adopted 2005 · last changed 2005
0.00
per decade
Ethiopia
0 events · adopted 1994 · last changed 1994
0.00
per decade
Iraq
0 events · adopted 2005 · last changed 2005
0.00
per decade
Japan
0 events · adopted 1946 · last changed 1946
0.00
per decade
Liberia
0 events · adopted 1986 · last changed 1986
0.00
per decade

Countries that keep starting over

Constitutional systems adopted since 1789.

How this is measured
Amending a constitution and replacing one are different acts, and the countries at the top of this list have done the second far more often than the first.

Three ways to have a constitution

Most countries keep one amendable document; a few, including the United Kingdom, do not.

How this is measured
The United Kingdom and New Zealand are governed by a body of statute, court decision and convention in which any part can be altered by an ordinary Act of Parliament. A third group, including Israel and Saudi Arabia, works from a set of basic laws rather than a single text. The comparative dataset records no amendment procedure for the uncodified pair, which would leave them off every board on this page. Instead they get the series that actually describes them: the statutes that changed the constitution.

United Kingdom

25 instruments · 1.43 per decade since 1900

The United Kingdom has a constitution but not a document. It is a body of statutes, prerogative powers, court decisions and conventions, and any of the statutes can be changed by an ordinary Act of Parliament. That is why the comparative dataset records no amendment procedure for it: there is nothing to amend, only law to replace.

The instruments25 since 1689
  1. 1689Bill of RightsSettled the terms on which the Crown holds power: no suspending laws, no taxation without Parliament, free elections, free speech in Parliament.
  2. 1701Act of SettlementFixed the succession and gave judges tenure during good behaviour rather than at the Crown's pleasure.
  3. 1707Union with Scotland ActMerged the English and Scottish parliaments into one Parliament of Great Britain.
  4. 1800Union with Ireland ActAdded Ireland to the union, in force from 1801.
  5. 1832Representation of the People ActThe Great Reform Act: redrew the borough seats and widened the franchise for the first time.
  6. 1867Representation of the People ActExtended the vote to urban working men, roughly doubling the electorate.
  7. 1884Representation of the People ActExtended the county franchise on the same terms as the boroughs.
  8. 1911Parliament ActRemoved the Lords' veto over money bills and replaced it with a delaying power.
  9. 1918Representation of the People ActNear-universal male suffrage and the vote for women over 30 with a property qualification.
  10. 1928Representation of the People (Equal Franchise) ActEqualised the franchise at 21 for women and men.
  11. 1931Statute of WestminsterEnded Westminster's power to legislate for the dominions without their request.
  12. 1949Parliament ActCut the Lords' delaying power from two years to one.
  13. 1958Life Peerages ActCreated appointed life peers, remaking the composition of the second chamber.
  14. 1969Representation of the People ActLowered the voting age from 21 to 18.
  15. 1972European Communities ActGave European law effect in the United Kingdom and priority over inconsistent domestic law.
  16. 1998Human Rights ActMade Convention rights enforceable in domestic courts and required legislation to be read compatibly where possible.
  17. 1998Scotland ActCreated the Scottish Parliament and defined what is reserved to Westminster.
  18. 1998Government of Wales ActCreated the National Assembly for Wales.
  19. 1998Northern Ireland ActPut the Belfast Agreement into law and created the Assembly and the power-sharing executive.
  20. 1999House of Lords ActRemoved all but 92 hereditary peers from the Lords.
  21. 2005Constitutional Reform ActSeparated the top court from the Lords, creating the Supreme Court, and reformed the Lord Chancellor's role.
  22. 2011Fixed-term Parliaments Actrepealed 2022Took the power to call an early election out of the Prime Minister's hands. Repealed in 2022.
  23. 2018European Union (Withdrawal) ActRepealed the 1972 Act and converted retained EU law into domestic law.
  24. 2020European Union (Withdrawal Agreement) ActGave effect to the withdrawal agreement and the transition period.
  25. 2022Dissolution and Calling of Parliament ActRestored the prerogative power to dissolve Parliament.

New Zealand

10 instruments · 0.56 per decade since 1900

New Zealand is the other pure case: no single constitutional document, no upper house since 1950, and a Bill of Rights that courts may interpret around but cannot use to strike down a statute.

The instruments10 since 1852
  1. 1852New Zealand Constitution ActPassed at Westminster, it created representative government and the provinces.
  2. 1867Maori Representation ActCreated four seats reserved for Maori voters.
  3. 1893Electoral ActGave women the vote, the first country in the world to do so in a national election.
  4. 1947Statute of Westminster Adoption ActTook up the independence the 1931 Statute offered.
  5. 1950Legislative Council Abolition ActAbolished the upper house, leaving a unicameral Parliament.
  6. 1975Treaty of Waitangi ActCreated the Waitangi Tribunal to hear claims under the Treaty.
  7. 1986Constitution ActRepealed the 1852 Act and gathered the core rules of government into one statute.
  8. 1990New Zealand Bill of Rights ActSet out civil and political rights, without the power to strike down legislation.
  9. 1993Electoral ActReplaced first past the post with mixed-member proportional representation, after a referendum.
  10. 2003Supreme Court ActEnded appeals to the Privy Council and created a domestic Supreme Court.

Counted as constitutional: statutes that condition the relationship between citizen and state in a general way or alter fundamental rights, which is the sense the courts use, plus the landmark extensions of the franchise. A count of these is not the same measure as an amendment rate, and the two are not compared above.

How long a constitution lasts

Measured across all 758 systems since 1789, counted as dead only when a later one replaced it.

How this is measured
Where a country ceased to exist, as Poland did in 1795, its constitution did not fail and is not counted as a death.

Survival

Half of all constitutions are gone within 14 years.

  • 5 yrs77%
  • 10 yrs60%
  • 25 yrs36%
  • 50 yrs23%
  • 100 yrs12%

Age protects

Chance of lasting another twenty years, given how long it has already stood. Unlike a machine, a constitution grows safer with age.

  • age 041%
  • age 1054%
  • age 2569%
  • age 5070%
  • age 10092%

Constitutions have become much harder to kill

WrittenConstitutionsMedian lifeReached 20 years
1789-18991989 yrs32%
1900-194511612 yrs29%
1946-198928715 yrs40%
1990-2025157not yet reached64%

More than half the constitutions written since 1990 are still standing, so their median life cannot be calculated yet. One written today is about twice as likely to see its twentieth birthday as one written in the nineteenth century.

The ones that bend, last

Among constitutions that survived their first ten years, those amended during that decade went on to last a median of 25 more years, against 16 for those left untouched (271 against 193 cases). A constitution that cannot be adjusted is not protected by its rigidity. It is endangered by it.

What this page can and cannot tell you

The source records every country in every year up to 2019. From 2020 it records constitutional events only, so a country with nothing listed since then has had no recorded change, rather than no data. 99 of the 196 countries here have done something constitutional since 2020, including thirteen that replaced their constitution outright. What the page cannot tell you is whether an event has gone unrecorded, which is why each row shows the year it last changed rather than claiming a state of affairs today.

There is also no forecast of how long any particular constitution will last. One was built and tested against the record: asked in 1999 how many of the world's constitutions would still stand in 2019, it said 92 and the answer was 135. A model that calibrates on the nineteenth century and expects collapse in the present is not a forecast, so it is not on this page.

There is deliberately no rigidity ranking here. A constitution can set out an elaborate amendment procedure and still be rewritten at will, and several are. Counting what was actually amended says more than scoring what the clause promises.

Data: Elkins, Zachary and Tom Ginsburg. 2026. Chronology of Constitutional Events, Version 6.0. Comparative Constitutions Project. Elkins, Zachary and Tom Ginsburg. 2025. Characteristics of National Constitutions, Version 5.0. Comparative Constitutions Project. comparativeconstitutionsproject.org. Built 2026-09-01.