How many electorates currently exist for the House of Representatives?

There are 151 electorates for the House of Representatives in Australia as of the 2025 federal election. The number is determined by the population-based calculation in section 24 of the Australian Constitution, which sets the House at 'as nearly as practicable, twice the number of the senators'.

The 151-seat figure has been in place since the 2019 federal election, after a redistribution increased Victoria from 37 to 38 seats and the ACT from two to three seats, with NSW reducing from 48 to 47. Earlier numbers were 150 (2010 to 2019), 150 (2007), 150 (2004), 150 (2001), and 148 (1998). The House grew steadily through the twentieth century from its original 75 members at federation in 1901, reflecting Australia's growing population and the constitutional nexus with the Senate.

Seats are distributed among the states and territories using a quota system. The Australian Statistician calculates each state's entitlement after each Census and at the start of each Parliament, using the population of each state divided by a quota (the total population of the six states divided by twice the number of state senators, currently 144). Rounding rules apply. The Constitution guarantees a minimum of five seats to each original state, meaning Tasmania (with about 575,000 people, far below the seat quota) keeps five seats regardless. Territories have separate seat entitlements based on similar calculations.

Electorate boundaries are drawn by the Australian Electoral Commission to produce roughly equal numbers of voters per electorate within each state, with a permissible variation of up to 10 per cent (or 3.5 per cent at the projected mid-term point of an upcoming election). Redistribution committees consider public submissions, geographic features, community of interest, communications and travel, and physical features when drawing boundaries. Major boundary changes regularly turn safe seats into marginal ones and vice versa, shaping the political map ahead of each federal election. Population growth in Victoria, Queensland, and Western Australia has been slowly shifting representation toward those states over recent decades.