The Basics

Instant runoff voting (IRV) is a ranked choice voting system for single-winner elections that, in a single round of counting, accomplishes the goal of a two-round runoff election. Sometimes called "ranked choice voting," "preferential voting," "majority voting" and "the alternative vote," IRV avoids the undemocratic outcomes of plurality voting that occur when so-called "spoilers" split the majority vote. By allowing voters to rank candidates in order of preference, IRV enables voters to vote their hopes instead of their fears, upholds the principle of majority rule and avoids the expenses and campaign spending associated with two rounds of voting.

Instant runoff voting is used to elect the national parliaments of Australia and Papua New Guinea, the president of Ireland and the leaders of governments in a growing number of cities, including London (United Kingdom), Wellington (New Zealand), Minneapolis and St. Paul in Minnesota, San Francisco and Oakland in California, and Portland (ME). IRV is also used to select the Best Picture Oscar and for leaders of hundreds of major private associations and student governments.

Explore this website for more information on how IRV works and where it is used. For more information on the benefits of IRV, see Why Use IRV?

How Instant Runoff Voting Works: Option One

  1. Instant runoff voting uses ranked choice ballots to simulate a traditional runoff in a single round of voting. Voters rank candidates in order of preference. They typically are given the option to rank as many or as few candidates as they wish. Indicating support for a lesser choice never counts your higher choices.
  2. Every voter has one vote. That vote is counted initially for a voter's first choice. .
  3. If there are more than two candidates who receive votes, the last-place candidate with the fewest votes is eliminated. More than one candidate can be eliminated simultaneously if their combined vote is less than the total of any other remaining candidate.
  4. Ballots counting for the eliminated candidate are added to the totals of the candidate ranked next on each ballot.
  5. This process of eliminating last-place candidates and adding ballots cast for those candidates to the totals of the next-ranked choice on that ballot continues until two candidates remain.  

The candidate with the majority of votes in this final round is declared the winner

How Instant Runoff Voting Works: Option Two

  1. Voters rank the candidates and those first choice rankings are tallied as in Option One.
  2.  The count is stopped at any point that a candidate as a majority of votes cast for continuing candidates - either by having a majority of first choice rankings or a majority of total votes in any round of counting.

Alternative approaches: Some jurisdictions limit potential winners to candidates who finish in the top two or top three in first choices. Some jurisdictions establish a limit on rankings. Some jurisdictions establish a winning threshold that is less than 50% of the vote (in which case they must limit winners to those in the top two in first choices.)

How Instant Runoff Voting Work: Video Animation

This animation explains the instant runoff voting counting process:

 

Other Explanations