International
Instant runoff voting (sometimes called in these nations other names like "preferential voting" in Australia) is used in the following countries:
- Australia, to elect its House of Representatives since 1918 / To elect most state and local legislators
- Republic of Ireland, to elect its president since 1938 (and multi-winner version used to elect is national parliament)
- United Kingdom to elect mayor of London since 2000 (supplementary vote form / To elect 13 other British city mayors / For Scottish local elections to fill vacancies / For leadership elections of Labour Party and Liberal Democratic Party
- New Zealand, to elect imayor of its capital city Wellington since 2004 and in several other New Zealand cities, include Dunedin (and multi-winner version for health boards all across the nation)
- Papua New Guinea, for parliamentary elections since 2004 (limited preferential voting variation with 3 rankings)
- Sri Lanka, to elect its president (contingent vote variation) since 1978
- Bosnia, for certain sub-national elections, since 2000
- Bougainville (autonomous region of Papua New Guinea) first used IRV (limited preferential voting format) for presidential elections in 2008 and for parliamentary elections in 2010
- Malta, indirect elections for its president (and multi-winner version for parliament)
- India for indirect elections for president and to parliamentary vacancies
- Canada's Conservative Party and Liberal Party for leadership elections / Other leadership election uses including Progressive Conservative Party of Alberta and Liberal Party of British Columbia
- Hong Kong's Legislative Council has four functional constituencies that use a preferential elimination system with a limited electorate