US election: Everything UK viewers need to know on the night – and when will we know who’s won?

The 2024 US election has arrived , with viewers from across the globe set to tune in as the next president of the United States is decided over the course of several hours.

Polls will close state by state at roughly 30-minute intervals from midnight, UK time . Each one will be a step closer to the presidency for either Kamala Harris or Donald Trump , the latter running for the third consecutive time since 2016.

Amongst the 50 states, six swing states will prove crucial for both candidates. These are: Arizona, Georgia, Michigan, Nevada, North Carolina, Pennsylvania and Wisconsin.

As with previous years, counting could take well into the day or even the day after to conclude in several states.

Viewers should be aware of how the US voting system works as polls close. To recap: the presidency is decided by the electoral college, rather than a simple count of which candidate gets the most votes.

The winner will be whichever receives a simple majority of 270 out of 538 electors from the 50 states. Each state counts for a different number of electoral college votes, with the winner of each state taking all the electoral votes.

In the UK, viewers can watch the results unfold on most news channels. To those following online, The Independent will be covering all the action live .

Here's a timeline of events for UK viewers:

By this time (5pm EST), polls will still be open in most states. It's far too early at this point to know which way the election is going, but the first exit polls will be released, giving some early hints.

This poll is not like the exit polls UK onlookers may be used to seeing at general elections. They are not based on voting outcomes, but rather what issues respondents have said mattered to them most at this election.

Tens of thousands of people will respond to this poll, giving a fairly accurate result. But knowing what issues motivated US citizens at the ballot box can only give a hint as to which way the final result will go.

Midnight - 1am UK time: First battleground results

After a couple of hours, polls will begin to close in more states. Between 7 and 8pm EST, nine states will see voting end.

Results at this stage may give a skewed view of how it's going for each candidate. Mr Trump is expected to receive the largest share of electoral college votes from this first round of states, so an apparent early lead can be expected.

What will be more important at this point are two key battleground states: Georgia and North Carolina.

Georgia will close first, with polls indicating that Mr Trump is slightly more likely to win the state. President Joe Biden won Georgia by just 0.2 percentage points in 2020, with Trump securing a more decisive 5-point victory in 2016.

Around half an hour later, polls will close in North Carolina. Securing the state would be a major win for Harris, with Trump taking it in both 2016 and 2020.

Polls to close in:

Holding 19 electoral votes – more than any other swing state – Pennsylvania will prove the most important result of the election. Whoever wins here will become the most likely candidate for the presidency.

It's also the most tightly contested state in the entire country. Trump won Pennsylvania in 2016 and lost it in 2020, giving an idea of how crucial it could prove.

"If we win Pennsylvania, we win the whole thing," he said in September, "it's very simple."

It's unlikely that many of the swing states will have called by this point. But the results that come from these first couple of rounds will prove pivotal. If either candidate secures Georgia, North Carolina and Wisconsin, it will be very difficult for the other to come back.

Polls to close in:

Within this hour, 15 more states will close. Among them will be three key battlegrounds: Arizona, Wisconsin and Michigan.

In 2016, Trump's victory in these 'blue wall' states was the deciding factor in securing him the presidency. By around 2.30am at that election, AP had called the race for the Republican nominee, with Hilary Clinton conceding a few minutes later.

By 3am, six out of seven swing states will have closed and may well have been called. Whatever happens next, the result may already be apparent.

Polls to close in:

Sometime between 3 and 4am, polls will close in the final swing state, Nevada. Representing only 8 electoral college votes, it's unlikely to be the decider.

At this point, what happens next will decide on how close the race has been so far. Doubtless, there will be a long wait for many states to call – some could take days.

But there could be enough to give a clear indication of who is on top. In the event of a landslide against either candidate, it's less likely that there could be much debate about who has secured the presidency.

But Trump has indicated he does not intend to concede defeat on the night, leading to fears he may make fresh allegations of electoral fraud, as he did baselessly in 2020. This is far more likely to happen if the result is close.

Polls to close in:

So, when will we know who's won?

It depends on the results. Four swing states – Arizona, Nevada, Pennsylvania and Wisconsin – have absentee ballot processes that can take days to conclude. If the result comes down to these states, then it could take days to find out who the new president is.

A similar situation unfolded in 2020, when Joe Biden was not declared president until four days after the election. On the other hand, the result was decided before the night had ended in 2016.

This year, if enough states have been called for either candidate to secure a majority without also needing any of these four swing states, they can safely be declared the winner.

It's important to be aware that when a state is 'called' on the news, this won't be the official, final result. News organisations will use unofficial results and projections when they announce a winner on the night or the day after.

This means that very close results in any state (especially swing states) could confuse things further, as analysts may not be able to make a clear-cut judgement.