How will Australia choose its next prime minister?

On 3 May Australians will head to the polls to vote in their first federal election since 2022.

The results will determine who the next prime minister will be, as well as the make-up of the nation's parliament.

Australia famously has a unique electoral system - and some quirky polling day traditions. Voting is mandatory for all citizens over 18, the country uses preferential voting, and picking up a "democracy sausage" is a polling day custom.

Almost 18 million people are registered to vote in this election - roughly 98% of those who are eligible.

Unlike the First Past the Post system - used in the UK and most US states - which elects candidates based on who has received the greatest number of votes in a single count, regardless of whether they've secured an absolute majority - voters in Australia rank candidates in order of preference.

If no candidate wins more than 50% of the vote in the first tally, the votes from the least popular candidates are then redistributed, and that process repeated until someone secures a majority.

In races for the House of Representatives, voters are required to mark a preference down for every single candidate listed on the ballot.

However, in Senate races, voters only need to mark down a designated number of preferences.

It is the leader of the party that receives the most seats in the House who then becomes prime minister. There is no separate leadership ballot.

All of the seats in Australia's House of Representatives - that's 150 in this election -will be up for grabs, as will 40 of the 76 seats in the Senate.

Australia has two major parties: the left-leaning Australian Labor Party and the conservative Liberal-National coalition.

One party needs to win at least 76 seats in the House to form a majority government.

If it cannot do that, it must try to win support from minor parties or independent MPs.

In both state and federal elections, the vote share for minor parties and independents has been steadily increasing in Australia for decades.

That reached record levels in the 2022 federal election, with one in three Australians casting votes for candidates outside the two major parties.

Labor formed a majority government after winning the 2022 election, which delivered the biggest loss for the Liberal Party since its inception.

As it stands, Labor has 78 seats in the House of Representatives, while the coalition has 57, with minor parties and independents splitting the remainder.

But with one House seat abolished, if Labor loses just two seats at this election it will be stripped of its majority in parliament.

In order to form a government in its own right, the coalition needs to win 19 seats, likely including many of those it lost to independent candidates during the 2022 vote.

Anthony Albanese has been the prime minister since the last election, and a stalwart of parliament for almost 30 years.

While he enjoyed a period of broad popularity after coming to power in 2022, he has in recent times come under pressure over his handling of divisive topics like housing, Indigenous affairs and both antisemitism and Islamophobia.

Albanese is being challenged by Peter Dutton, who became head of the Liberal-National coalition after their 2022 defeat. He is contesting his first election as opposition leader.

Known as a staunch conservative, Dutton has years of experience in important ministerial portfolios - like defence and home affairs - but has been a controversial figure at times, particularly on social issues.

Both the polling and the political messaging around this year's election indicate that cost of living is the biggest concern for many voters.

Since the 2022 election, inflation - which is now slowing - has pushed up the prices of everyday essentials such as food and utilities, leaving many households feeling stretched.

The Albanese government has implemented a string of policies that it says are aimed at providing relief, such as keeping the cost of medications down, and offering tax cuts, energy rebates and rental assistance to those eligible.

However, Australia has raised interest rates 12 times since Albanese was elected in May 2022 - something that is done independently of government but seen to reflect their economic management - and that has put additional pressure on borrowers and those with mortgages across the country.

Housing affordability will also be a key issue this election cycle, with several Australian cities among the most expensive in the world for homebuyers.

Historically, Australians are used to getting a result and knowing who will form government on election night.

However, it is usually not the Australian Election Commission - the official body tasked with manually counting the votes - that declares this.

Instead, the AEC provides what's known as an "indicative count" throughout the day, which media commentators, election experts and sometimes even the parties and candidates themselves then base their calls on.

The AEC does not formally declare a seat until it is confident the result will not change based on the number of uncounted votes, which can sometimes take days.