A runoff election is a further election held to determine a winner when the rules of the initial contest require an additional vote because no candidate has satisfied the required winning condition. The most familiar form is a two round system in which candidates compete in an initial round and, if no candidate obtains the required absolute majority, a second round is held.
In the common majority runoff form, the two candidates with the highest first round totals proceed to the second round, and the candidate who wins the runoff becomes the elected candidate. The precise rules vary between jurisdictions. Some systems require a majority in the first round, while others use a different threshold or permit more than two candidates to participate in the second round.
A runoff is therefore not itself a complete electoral system in every context; it is a stage or mechanism used within certain electoral systems. Its defining feature is the existence of a subsequent contest designed to resolve an election that was not settled under the first round's rules.
In a conventional two round majority system, the first round resembles an ordinary plurality election. Voters choose among several candidates, and the votes are counted. If one candidate obtains an absolute majority, usually more than half of valid votes under the relevant rule, that candidate wins immediately and no runoff occurs. If nobody reaches the required threshold, a second round takes place.
The most common version limits the second round to the two leading candidates, although the detailed rules can differ. The second round then becomes a direct contest in which voters choose between the remaining candidates. This structure distinguishes a runoff from a recount because the second round is a new electoral event involving a new opportunity to vote, rather than a second calculation of the same ballots. It also distinguishes a runoff from a ranked preferential system because preferences are not necessarily transferred from one candidate to another; instead, voters may return to the polls and make a fresh choice among the candidates who remain eligible.
The main institutional purpose of a runoff is to establish a winner with the required level of support when the initial field of candidates is too fragmented to produce that result. Suppose five candidates receive 35, 28, 20, 10 and 7 percent respectively. Under a simple plurality system, the candidate with 35 percent would win. Under a majority runoff system requiring more than half the vote, the first round would not settle the contest.
The leading two candidates would proceed to a second round, where supporters of eliminated candidates could choose between them, abstain or otherwise participate according to the applicable rules. The second round can therefore change the coalition of voters supporting the eventual winner. The first round measures support in a broad candidate field, while the second round tests support in a narrowed contest. The resulting electoral dynamics can involve endorsements, coalition negotiations, tactical voting and changes in campaign messaging between rounds. These are consequences of the two stage structure rather than intrinsic requirements of every runoff system.
Runoff elections are commonly associated with presidential elections, but they can also be used for legislative or other offices. In presidential systems, a runoff may be used when the constitution requires the president to obtain an absolute majority or another specified threshold. In legislative elections, a two round system can operate in single member constituencies, with the second round determining which candidate takes the seat. The rules governing eligibility for the second round vary.
A majority runoff normally advances the two highest vote getters, whereas other two round arrangements can permit more candidates if they meet particular thresholds. This distinction matters because the phrase runoff election does not by itself specify the precise qualifying rule. The term describes the additional contest, while the electoral law determines who participates, what threshold triggers it, how many candidates can proceed, how long separates the rounds and what vote threshold determines victory. Comparative analysis must therefore distinguish the general concept from the specific legal model adopted by a jurisdiction.
A runoff differs from the Alternative Vote even though both can produce a majority winner. Under the Alternative Vote, voters rank candidates on a single ballot. If no candidate has the required majority, the lowest candidate is eliminated and votes are transferred according to the next preferences marked by voters. This process continues until a candidate reaches the required threshold.
A traditional runoff instead involves separate rounds of voting, meaning voters may have another opportunity to reconsider their choice after seeing the first round result. The two mechanisms therefore collect preference information differently. Ranked voting obtains information about subsequent preferences at the initial election, while a runoff obtains a new vote after the candidate field has been narrowed. The distinction affects campaign timing, voter behaviour, administrative costs and the role of post first round political negotiations. It also means that the outcome of a runoff cannot simply be described as a mechanical transfer of first round votes. Voters make decisions in a changed political environment.
Runoffs require additional administrative and political resources because a second polling event must be organised unless the system uses a special procedure. Electoral authorities may need to print new ballots, reopen polling stations, communicate eligibility rules, conduct another count and certify another result. Voters may face a second campaign period and candidates may need to alter their strategies. The interval between rounds can range from a short period to several weeks depending on the legal framework.
During this period, candidates who were eliminated may endorse one of the remaining candidates, parties may negotiate support and voters may reassess their choices. Turnout can also differ between rounds, meaning the electorate participating in the final contest may not be identical to that participating in the first. Consequently, a runoff creates a sequential electoral process rather than merely extending the original count. The institutional consequences depend on the rules governing the second round and the behaviour of voters and political organisations between rounds.
The term runoff can also be used more broadly for a second contest triggered when an initial contest fails to produce a winner under the applicable rules. Election terminology is therefore jurisdiction dependent. A runoff might follow a primary election, a general election or another preliminary contest, and the qualifying threshold may vary.
The NIST election glossary describes a runoff as an election used to select a winner after an earlier contest in which no candidate achieved the required minimum percentage, with the two highest candidates proceeding in the definition it provides. This illustrates why the legal definition in a particular jurisdiction should be consulted rather than assuming that every runoff automatically means a two candidate presidential second round. In comparative politics, however, the classic two round system remains the principal reference point.
A runoff should therefore be distinguished from several related concepts. It is not a recount because a recount reexamines existing ballots rather than asking voters to cast new ballots. It is not a by election because a by election fills a vacancy in an office between scheduled elections. It is not necessarily a snap election because a runoff can be a scheduled component of an electoral system rather than an unexpectedly early election.
It is not necessarily a general election because a runoff may concern a single office or constituency. It is also not synonymous with the two round system in every technical context, although the terms are frequently used together because the runoff is the second round of a two round election. Understanding these distinctions is essential when analysing electoral calendars, constitutional rules and election results. The central defining characteristic remains sequential voting: an initial contest is followed by another contest because the first contest did not produce a winner under the applicable electoral rule.
