How many senators represent each state in the Australian Parliament?

Twelve senators represent each of the six Australian states in the Australian Senate. In addition, each of the two mainland territories (the Australian Capital Territory and the Northern Territory) returns two senators. The total membership of the Senate is therefore 76 senators (12 from each of six states, plus 2 from each of the two territories).

Equal state representation is one of the foundational principles of Australian federalism. Section 7 of the Australian Constitution requires that the Senate be composed of senators for each state, directly chosen by the people of the state, and that each original state shall have an equal number of senators. The equal-state principle ensures that smaller states like Tasmania (with about 575,000 people) have the same voice in the Senate as New South Wales (about 8.4 million people), balancing the population-based representation in the House of Representatives.

The number of senators per state has been amended twice through legislation under section 7. The original six per state set in 1901 was increased to ten per state in 1948 and to twelve per state in 1984. Each increase required corresponding adjustments to the House of Representatives under the constitutional nexus that requires the House to be 'as nearly as practicable, twice the number of the senators'.

State senators serve six-year terms, with half elected at each federal election under a system of rotation. Territory senators serve three-year terms aligned with each House of Representatives election. Senators are elected by single transferable vote, a form of proportional representation that allows smaller parties and independents to win seats. The Senate has 76 members in total, making the federal Parliament's combined membership 227 (151 House plus 76 Senate). The President of the Senate, elected by senators at the start of each Parliament, presides over Senate proceedings.