General · EdgepediaSeptember 17, 20266 min read

Electoral threshold

An electoral threshold is the minimum share of votes that a party must obtain to win representation in a legislature. Thresholds appear mainly in proportional representation (PR) systems, where seats are allocated in rough proportion to votes, and they exist to keep very small parties out of parliament. International IDEA's glossary distinguishes a formal threshold, a figure written into the constitution or electoral law, usually a percentage of valid votes cast, from the effective or natural threshold, a mathematical by-product of the electoral system itself, of which district magnitude is the most important feature.¹

Key fact	Detail
Definition	The minimum level of support a party needs to gain representation in the legislature; may be formal (in law) or effective (a by-product of district magnitude and other rules)¹
Typical legal levels	Most PR countries set the bar between 3% and 5%, with outliers on both ends²
Natural threshold example	In a four-seat PR district, any candidate above 20% is elected and any candidate below about 10% is unlikely to be elected³
Wasted votes, Germany 2013	FDP (4.8%) and AfD (4.7%) both missed the 5% threshold; about 15.7% of voters, 6.86 million people, had votes with no effect⁴
Extreme case, Turkey 2002	With a 10% threshold (since reduced to 7%), 46% of votes were lost and a party with 34% of the votes won almost a two-thirds majority⁵
Determinants of the effective threshold	Effective thresholds decline with both district magnitude and electoral fragmentation⁶
Constitutional limits	Germany's Federal Constitutional Court held in 2024 that the 5% threshold in the current Federal Elections Act is unconstitutional in its present form but continues to apply under certain conditions⁷

Formal and effective thresholds

A formal threshold is a number fixed in law. Parties below it receive no seats, even where district magnitude would otherwise have allowed them to win representation; legal thresholds can therefore deny many parties seats that the district arithmetic alone would have granted.⁸ Even systems with no formal threshold retain an implicit barrier, the effective threshold, driven by the number of seats available in each district.²

The IDEA handbook illustrates the natural threshold with district magnitude: in a district with four seats under PR, a candidate with more than 20% of the vote is certain of election, while a candidate below about 10% is unlikely to be elected, the exact figure varying with the configuration of parties, candidates, and votes.³ In majoritarian systems the natural threshold corresponds to the smallest plurality share needed to win a district seat, typically around 1/M for a district of magnitude M.⁹

Recent modeling work treats the effective threshold as the vote share at which a party has an equal chance of winning its first seat in a district. A logical model by Jack Bailey, a political scientist working on electoral systems, derives this threshold from two quantities, district magnitude and the effective number of vote-winning parties, and finds that effective thresholds decline as districts grow larger and as the party system becomes more fragmented.⁶ Whether the district magnitude or the national legal threshold is more constraining varies from country to country; sometimes one binds and sometimes the other.⁸

Purposes and effects

Designers raise the threshold for representation when they want to limit party fragmentation driven by personality or ethnicity, and to push small parties into coalitions.¹ Thresholds are used to promote stability and governability by preventing the election of parties with very small representation.⁵ Empirically, PR with a threshold restricts the effective number of electoral parties to a level on a par with single-member plurality systems, largely because smaller groupings with spatially concentrated support are absent.¹⁰

Wasted votes. The main cost is votes cast for parties that fail to clear the bar. In Germany's 2013 Bundestag election, the Free Democrats at 4.8% and Alternative for Germany at 4.7% both just missed representation, and about 15.7% of voters, 6.86 million people, found their votes had no effect because of the hurdle.⁴ In the 2019 election for the French members of the European Parliament, the 5% threshold produced 19.8% wasted votes.⁵

Disproportionality. Turkey illustrates the extreme. Its 10% national threshold, combined with the D'Hondt formula (seat-allocation method favoring larger parties), reduced splinter parties and increased disproportionality in favor of larger parties.¹¹ In the 2002 election only two parties surpassed the threshold, 46% of votes were lost, and the AKP secured almost two-thirds of the seats with 34% of the vote; the threshold was later reduced to 7%.⁵ The same authors note that fear of a wasted vote prompts supporters of small parties to switch to their second-best option, concentrating votes among large parties, a pattern they link to Duverger's psychological effect.¹²

Constitutional and judicial limits

Courts have policed thresholds where they conflict with constitutional principles of equal representation. The German Federal Constitutional Court, in a judgment of 30 July 2024, upheld the second-vote basis procedure of the 2023 Federal Elections Act but held that the 5% electoral threshold in § 4(2) of the Act violates the Basic Law in its current version, while continuing to apply under certain conditions.⁷ Earlier, in 2011 and 2014, the same court declared Germany's thresholds for European Parliament elections, first 5% and then 3%, unconstitutional.¹³ In Indonesia, the Constitutional Court's Decision 116/PUU-XXI/2023 treated the 4% parliamentary threshold as applicable only to the 2024 election and conditionally constitutional for future elections, a shift from earlier rulings that had treated it as open legal policy.¹⁴

Reducing wasted votes

One proposed remedy is the replacement vote (Ersatzstimme, sometimes translated as spare vote), discussed extensively in Germany, under which voters indicate a second-choice party or rank a subset of parties, and votes for parties below the threshold are reallocated.⁵ A formal model of party voting with thresholds compares many such reallocation rules axiomatically and experimentally using data collected during the 2024 European election in France, and identifies three particularly attractive rules: Direct Winners Only (DO), Single Transferable Vote (STV), and Greedy Plurality (GP).⁵ Naively, a tradeoff appears between the wasted-vote problem and the risk of political fragmentation that thresholds are meant to control.⁵

References

Topic: Encyclopedia › Society and history › Politics and government › Elections and representation › Electoral systems and principles › Voting systems › Proportional and mixed systems › Thresholds, district magnitude, and PR design parameters

Initially written Sep 17, 2026 · Reviewed: Oct 25, 2026 · Edited: Oct 15, 2026; Oct 25, 2026 · Last review: Oct 25, 2026

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