US election 2024: When will Australia know whether Donald Trump or Kamala Harris has won?

Millions of Americans have voted in the US presidential race between former President Donald Trump and Vice President Kamala Harris with polling booths reporting the numbers and multiple states already called.

We are about to get a definitive answer as to who will occupy the world's most powerful political office from January 2025.

When do polls close in the US presidential election?

In the eastern states, the earliest polling booths closed by mid morning on Wednesday AEDT. By 1pm AEDT all voting will have ceased in almost 30 states, including crucial swing electorates like Pennsylvania, Michigan, North Carolina and Wisconsin.

While all eyes are on the state of play in the 'battleground' electorates, we know enough that more than a dozen states have been already officially called by the Associated Press.

When will we know who the winner is?

When Donald Trump shocked much of the world and beat Hillary Clinton in 2016, the election result was conceded on the night (late afternoon AEDT).

However last election in 2020, counting dragged well into the weekend before Joe Biden was declared the winner. If the polls heading into the election were indication, the latter was perhaps more likely scenario than the former this year. So we could be waiting days. But currently, Trump has an early edge.

Will Trump accept the result?

Speaking to reporters after casting his vote in Florida this morning AEDT, Trump expressed confidence in the day's turnout and said his campaign was perhaps his best yet.

We did great in the first one, we did much better in the second one but something happened," he added, alluding to his consistent and false claims the election was "stolen" when he lost to Joe Biden four years ago.

When asked about potentially declaring victory regardless of the results today, Trump responded, "I don’t know what’s going to happen," adding, "If it’s a fair election, I’d be the first one to acknowledge [the results]."

Why the election winner could take 'several days'

The election will come down to seven key swing states, with specific rules that govern their count.

On a call with reporters on Monday (local time), the Harris campaign said it expects near-complete results on election night in states like North Carolina, Georgia and Michigan. However other 'battleground' states like Arizona, Nevada and perhaps most importantly, Pennsylvania, could take several days to produce a winner.

"We may not know the results of this election for several days, but we are very focused on staying calm and confident throughout this period as the process goes through," Harris campaign Chair Jen O'Malley Dillon said.

Why Pennsylvania could be the sticking point

In the so-called electoral college system (explained further here) each state is worth a certain number as candidates try to reach the magic mark of 270 for victory. Trump and Harris both have about 220 'votes' reliably sewed up, unless anything totally unexpected takes place. Then there are some 93 more available in the seven battleground states (mapped above).

Of them, the biggest is Pennsylvania which carries 19 electoral college votes. While a number of scenarios are possible, it's likely the road to the White House goes through Pennsylvania.

"It is mathematically possible for either to win without Pennsylvania, but it's difficult," Dennis Altman, Emeritus Professor of Politics at LaTrobe University, told Yahoo News Australia.

"It’s very likely whoever wins Pennsylvania, wins the election."

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Officials in Pennsylvania are not allowed to start counting early mail-in votes until the official polling day, when they're of course already busy. The state also has a law in place which means a statewide recount would be required if there’s a half-percentage-point difference between the winner and the loser. In 2020, Biden won it with 50 per cent of the vote to Trump's 48.8 per cent.

Trump acknowledged the possibility of the count dragging on for days in the state of Pennsylvania if it comes down to the wire and no winner is called today.

"If think it's an absolute outrage if that's the case," he told reporters in Florida this morning after casting his ballot.

Strap in.

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