# Two-round system
The two-round system (TRS) is an electoral method in which voters cast a single vote for a candidate, and if no candidate wins an overall majority, defined as 50 percent plus one of the valid votes cast, a second round is held, typically between the two leading candidates[1](https://peacemaker.un.org/sites/default/files/document/files/2023/02/electing-presidents-presidential-and-semi-presidential-democracies.pdf). It belongs to the plurality-majority family of electoral systems, and majoritarian systems such as the Alternative Vote and the two-round system share the aim of ensuring that the winning candidate receives an absolute majority[2](https://www.aceproject.org/ace-en/topics/es/onePage).
| Key fact | Detail |
|---|---|
| Winning threshold | First round: 50 percent + 1 of valid votes; normally an absolute majority, although several countries use a different figure when electing a president[1](https://peacemaker.un.org/sites/default/files/document/files/2023/02/electing-presidents-presidential-and-semi-presidential-democracies.pdf) • [3](https://peacemaker.un.org/sites/default/files/document/files/2022/07/ideaelectoralsystemdesign-thenewinternationalideahandbook2005.pdf) |
| Runoff participants | The two leading candidates from the first round[1](https://peacemaker.un.org/sites/default/files/document/files/2023/02/electing-presidents-presidential-and-semi-presidential-democracies.pdf) |
| Presidential use | Since the global wave of democratization in the 1990s, the most common way of directly electing presidents[1](https://peacemaker.un.org/sites/default/files/document/files/2023/02/electing-presidents-presidential-and-semi-presidential-democracies.pdf) |
| Countries (presidential) | France, Nigeria, Brazil, Indonesia, Kenya, Cote d'Ivoire, Senegal, Zambia (since 2016), among others[1](https://peacemaker.un.org/sites/default/files/document/files/2023/02/electing-presidents-presidential-and-semi-presidential-democracies.pdf) |
| Legislative use | Used to elect 22 national legislatures; France uses a majority-plurality variant for its legislative elections[3](https://peacemaker.un.org/sites/default/files/document/files/2022/07/ideaelectoralsystemdesign-thenewinternationalideahandbook2005.pdf) |
| Party-system effect | Lower barriers to entry for third parties or new political movements than plurality systems; encourages pre-electoral agreements between large and small parties[1](https://peacemaker.un.org/sites/default/files/document/files/2023/02/electing-presidents-presidential-and-semi-presidential-democracies.pdf) • [4](https://eos.cartercenter.org/summaries/4) |
## How it works
All candidates appear on the first ballot. If one candidate receives a majority, that candidate is elected and no second round is needed[5](https://usafacts.org/articles/runoff-election-definition/). If no candidate reaches the majority threshold, the two candidates with the most votes advance to a second round, or runoff, held at a later date[1](https://peacemaker.un.org/sites/default/files/document/files/2023/02/electing-presidents-presidential-and-semi-presidential-democracies.pdf) • [5](https://usafacts.org/articles/runoff-election-definition/).
Variants differ in the qualifying rule and the second-round threshold. In French regional elections, lists qualify for the second round at a threshold of 12.5 percent of registered electors, and in the second round only a relative (plurality) majority is needed to win[6](https://www.venice.coe.int/webforms/documents/default.aspx?pdffile=CDL-EL%282003%29006rev-e). The [International IDEA](https://www.edgepedia.org/international-idea) handbook distinguishes the standard majority-majority form from the majority-plurality variant, in which an absolute majority is required only in the first round[3](https://peacemaker.un.org/sites/default/files/document/files/2022/07/ideaelectoralsystemdesign-thenewinternationalideahandbook2005.pdf). Timing also varies by country: Iran's law requires the runoff between the top two vote getters to take place within one week of the first round[7](https://aceproject.org/today/newsletter/april-2009-print-edition), while in Turkey's 2023 schedule the second round followed the first by two weeks[8](https://apnews.com/article/f2a75ed9d0569459c8dade26c694422c).
## Where it is used
For presidential elections, the two-round system spread widely after the democratization wave of the 1990s and became the most common method of directly electing presidents worldwide[1](https://peacemaker.un.org/sites/default/files/document/files/2023/02/electing-presidents-presidential-and-semi-presidential-democracies.pdf). The IDEA handbook reports that two-round systems are used to elect 22 national legislatures as well[3](https://peacemaker.un.org/sites/default/files/document/files/2022/07/ideaelectoralsystemdesign-thenewinternationalideahandbook2005.pdf).
Recent examples show the system in operation. In [North Macedonia](https://www.edgepedia.org/north-macedonia)'s 2024 presidential contest, the runoff of a two-round contest began in April and concluded in May, running alongside a parliament elected in a single round[9](https://apnews.com/article/16d5e8870f2587b2a0172dbff07578b8). In Peru's 2026 presidential election, none of 35 candidates secured an outright victory, sending the top two to a June runoff[10](https://apnews.com/article/49e6a05c3b8ea5ccb141b925f7e92a83). Portugal's January 2026 presidential ballot went to a second round for the first time since 1986, only the second such election since democracy began there in 1976[11](https://www.lemonde.fr/en/international/article/2026/01/18/portugal-votes-in-a-presidential-election-full-of-uncertainty_6749546_4.html). In the United States, the Constitution leaves states free to set runoff rules for congressional elections, and states usually hold runoffs when no candidate receives a majority in the first election[5](https://usafacts.org/articles/runoff-election-definition/). Georgia and Louisiana are the two states that require a runoff in all general elections if no candidate achieves at least 50 percent of the vote[12](https://time.com/6232641/georgia-runoffs-racist-history-warnock-walker/).
## Effects on parties and candidates
Compared with a single-round plurality system, the two-round system lowers the barriers to entry faced by third parties or new political movements, making the system more responsive to changing societal needs[1](https://peacemaker.un.org/sites/default/files/document/files/2023/02/electing-presidents-presidential-and-semi-presidential-democracies.pdf). Because the runoff does not reward a mere plurality in the first round, more serious candidates run than under first-past-the-post, a prediction political scientists trace to Maurice Duverger's work; the runoff system is traditionally grouped with proportional systems in this respect[13](https://www.sciencedirect.com/science/article/pii/S0176268016302415). Two-round ballots also tend toward bipolarization of political life, or at least toward pre-electoral agreements between large and small parties[4](https://eos.cartercenter.org/summaries/4). A regression discontinuity study of Italian municipalities, where cities above 15,000 inhabitants elect mayors by runoff while smaller cities use a single round, confirmed predictions that runoffs increase the number of candidates and reduce policy volatility, and found that candidates' strategic responses explain a larger part of the effect[14](https://pubs.aeaweb.org/doi/10.1257/aer.20131024) • [15](https://www.imf.org/-/media/files/publications/wp/2021/english/wpiea2021227-print-pdf.pdf).
The system also shapes voter behavior. Áron Kiss, a political scientist who studies strategic voting, proposed a method to identify strategic ('wasted vote') behavior using two-round elections in which the runoff features three candidates, exploiting Hungarian elections between 1990 and 2010; the analysis found evidence for increasing strategic voting in post-transition Hungary[16](https://www.sciencedirect.com/science/article/pii/S0261379415001560). In the other direction, research cited in an IMF working paper finds that third-placed and lower candidates receive higher vote shares in two-round elections, suggesting voters behave less strategically when a second round gives their first-round vote a signaling role[15](https://www.imf.org/-/media/files/publications/wp/2021/english/wpiea2021227-print-pdf.pdf).
## Costs and criticisms
The runoff is a distinct election with its own campaign period, observation needs, and integrity risks[17](https://voterights.org/glossary/two-round-system), and holding it adds delay, cost, and administrative complexity[1](https://peacemaker.un.org/sites/default/files/document/files/2023/02/electing-presidents-presidential-and-semi-presidential-democracies.pdf). In the United States, Georgia's runoff carries a contested history: it was introduced in 1963 by state representative Denmark Groover, an avowed segregationist, after he lost a 1958 race he blamed on Black "bloc voting," on the reasoning that a runoff would rally white voters around a white candidate and decrease the likelihood of an African American being elected[12](https://time.com/6232641/georgia-runoffs-racist-history-warnock-walker/).
Assessments of representation are mixed. FairVote's comparison of voting methods finds that two-round runoffs outperform plurality voting in electing politically representative groups of public officials, but that little evidence finds they improve election rates for women or people of color[18](https://fairvote.org/resources/electoral-systems/comparing-voting-methods/).
## Comparison with instant-runoff voting
[Instant-runoff voting](https://www.edgepedia.org/instant-runoff-voting) (IRV), also called ranked choice voting or the alternative vote, replaces the separate second election with a ranked ballot on which the weakest candidate is eliminated and those ballots are redistributed until one candidate has a majority[19](https://time.com/5718941/ranked-choice-voting/). Both are single-winner majority methods in the plurality-majority family, and electoral-system software treats plurality, two-round runoff, and single transferable vote as distinct implementable rules[20](https://arxiv.org/abs/2102.05801). IRV descends from the single transferable vote invented in the 1850s by Thomas Hare in England and Carl Andrae in Denmark[21](https://archive.fairvote.org/irv/vt_lite/history.htm), while the two-round system keeps two physical trips to the polls but lets voters reconsider their choice with full knowledge of the field that survived the first round.
## References
1. [Electing Presidents in Presidential and Semi-Presidential Democracies, UN Peacemaker](https://peacemaker.un.org/sites/default/files/document/files/2023/02/electing-presidents-presidential-and-semi-presidential-democracies.pdf)
2. [ACE Electoral Knowledge Network: Electoral Systems topic page](https://www.aceproject.org/ace-en/topics/es/onePage)
3. [Electoral System Design: The New International IDEA Handbook (2005), Two-Round System chapter](https://peacemaker.un.org/sites/default/files/document/files/2022/07/ideaelectoralsystemdesign-thenewinternationalideahandbook2005.pdf)
4. [The Carter Center, Election Standards: two-round ballots](https://eos.cartercenter.org/summaries/4)
5. [What is a US Congressional Runoff Election, USAFacts](https://usafacts.org/articles/runoff-election-definition/)
6. [Venice Commission, CDL-EL(2003)006rev, on French electoral rules](https://www.venice.coe.int/webforms/documents/default.aspx?pdffile=CDL-EL%282003%29006rev-e)
7. [ACE Newsletter April 2009: A Primer on Iran's Presidential Election System](https://aceproject.org/today/newsletter/april-2009-print-edition)
8. [Erdogan announces Turkish elections to be held on May 14, AP News](https://apnews.com/article/f2a75ed9d0569459c8dade26c694422c)
9. [North Macedonia holds presidential and parliamentary elections Wednesday, AP News](https://apnews.com/article/16d5e8870f2587b2a0172dbff07578b8)
10. [Peru faces a presidential runoff as election count drags on, AP News](https://apnews.com/article/49e6a05c3b8ea5ccb141b925f7e92a83)
11. [Portugal votes in a presidential election full of uncertainty, Le Monde](https://www.lemonde.fr/en/international/article/2026/01/18/portugal-votes-in-a-presidential-election-full-of-uncertainty_6749546_4.html)
12. [Georgia's Runoff Elections Have a Racist History, TIME](https://time.com/6232641/georgia-runoffs-racist-history-warnock-walker/)
13. [Single round vs. runoff elections under plurality rule: A theoretical analysis, Electoral Studies](https://www.sciencedirect.com/science/article/pii/S0176268016302415)
14. [Moderating Political Extremism: Single Round versus Runoff Elections under Plurality Rule, American Economic Review](https://pubs.aeaweb.org/doi/10.1257/aer.20131024)
15. [When Do Politicians Appeal Broadly? The Economic Consequences of Electoral Rules in Brazil, IMF WP/21/227](https://www.imf.org/-/media/files/publications/wp/2021/english/wpiea2021227-print-pdf.pdf)
16. [Identifying strategic voting in two-round elections, Electoral Studies](https://www.sciencedirect.com/science/article/pii/S0261379415001560)
17. [Two-round system, VoteRights glossary](https://voterights.org/glossary/two-round-system)
18. [Comparing single-winner voting methods, FairVote](https://fairvote.org/resources/electoral-systems/comparing-voting-methods/)
19. [New York City Voters Just Adopted Ranked-Choice Voting, TIME](https://time.com/5718941/ranked-choice-voting/)
20. [The vote Package: Single Transferable Vote and Other Electoral Systems in R, arXiv](https://arxiv.org/abs/2102.05801)
21. [The History of IRV, FairVote archive](https://archive.fairvote.org/irv/vt_lite/history.htm)
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*Topic: Encyclopedia › Society and history › Politics and government › Elections and representation › Electoral systems and principles › Voting systems › Plurality and majority systems › Two-round and runoff systems*
*Initially written Sep 17, 2026 · Reviewed: Sep 30, 2026; Oct 25, 2026 · Edited: Sep 30, 2026; Oct 25, 2026 · Last review: Oct 25, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license