In the Senate, 12 senators are elected to represent each state and two senators are elected to represent each territory. State senators are elected for a period of 6years using a system of rotation that ensures only half the state senators end their term every 3 years. Territory senators are elected for a period of 3 years at the same time as the members of the House of Representatives.
Senators are elected using a system of proportional voting, designed to allocate seats to candidates in proportion to the votes cast in an election.
There are 151 members elected to the House of Representatives—one for each of Australia's 151 electorates. An average of 100 000 voters live in each electorate. Each member is elected using a system of preferential voting, designed to elect a single member with an absolute majority for each electorate.
For further information about voting see the Australian Electoral Commission website.