Millions of Americans will head to the polls on 5 November to elect the next president of the United States.
Seats in the Senate and the House of Representatives are also up for grabs across the country, but the focus of this election for many across the US and the world will be on who between Donald Trump or Kamala Harris replaces Joe Biden in the White House.
While polling stations will be closed by the evening of election day, the time taken to tally up many millions of votes – and some nuanced differences in election laws between states – means that it could take anywhere from several hours to a few days or even weeks until the winner is known, depending on how close the race ends up being.
Here’s a guide to how votes are counted, how long it could take, how the result can be called before the count has finished, and how recounts work.
How are votes counted at the US election?
The exact way in which votes in the US election are counted depends on the method by which voters have submitted their ballot.
For example, if physical paper ballots are used at voting centres, the ballot boxes are then sealed and delivered to a vote-counting centre, where election staff begin the process of counting them.
At polling stations where digital voting machines are used, election officials send voter data – either electronically or by hand – to the counting centre, where the results are then processed.
Some states allow votes cast during early voting periods to be counted prior to election day, but results will not be published until polls close. However, other states only begin counting any early votes alongside those cast on election day itself.
Things vary similarly on a state-by-state basis for mail-in ballots, which again influences how quickly the overall results of an election can be declared and certified.
Mail-in ballots must go through processing to ensure any requirements were followed. For example, the outside envelope of every mail-in ballot must be signed by the voter, with some states requiring additional verification such as the signature of a witness or a notary.
This processing is permitted before election day in many states, but not all.
Ballots are then counted, with votes tallied up. Some states allow mail-in ballots to be both processed and counted before election day as long as results are not published until after polls close, with the majority allowing the counting to commence only on election day itself.
While every ballot counts towards the popular vote, perhaps the most important function of ballots cast by voters in the US election is to inform the designated electors from their states how to vote.
That’s because the candidate who wins the popular vote is not necessarily the person who wins the election. In fact, two of the five elections in American history where the popular vote winner did not end up becoming president have happened this century: 2000 and 2016, namely George W Bush vs Al Gore and Donald Trump vs Hillary Clinton.
Instead, the victor is the candidate that wins the electoral college – a system that has been in place in one form or another since the US Constitution came into effect in 1788.
It consists of 538 electors, the majority – 270 – of whose votes is needed to win the presidency.
Guided by the votes of the American people, every state’s electors cast votes for president and vice-president on 17 December, at a meeting of the electoral college.
These votes are counted and certified in the chamber of the House of Representatives on 6 January, with the new president taking office later that month.
How long does it take to count all the votes?
While the majority of votes in many states will have been counted within 24 hours of polls closing, if not the same night, factors such as state-by-state differences in pre-election day ballot processing and even the methods Americans use to cast their votes can mean that some votes are still being counted days after the election.
For example, mail-in ballots in some states such as Nevada can be counted if received by 9 November – four days after in-person polls have closed – as long as they are postmarked by election day.
It’s therefore difficult to say exactly how long it will take to count all of the votes in the 2024 US election, even though the speed at which the process is completed is generally expected to be quicker than the last election in 2020.
Then, it took several days for either candidate to pass the 270 electoral college votes required, with that only being achieved when key swing state Pennsylvania declared for Biden.
Even at that point, votes were still being counted across the country, within it possible that the process could go on for more than a week after election day itself.
Why is the result normally called before all votes are counted?
The result of the election can usually be called before all votes are counted if one candidate passes the 270 mark in the electoral college, meaning they have won the majority required for the presidency.
Unless a race is historically close, this typically is achievable while votes are still being counted in some states.
Even before a electoral college majority has officially been reached, the result is normally called by polling experts and the media.
Taking into account historical trends, news outlets use the unofficial vote totals being reported along with exit polling and the number of votes that are still outstanding to project the winners.
The Associated Press, for example, is one such media outlet whose predictions serve as the basis for many other newspapers. Describing how and when it calls an election, it says: “Only when AP is fully confident a race has been won – defined most simply as the moment a trailing candidate no longer has a path to victory – will we make a call.
For example, in the 2020 presidential election, the AP declared Biden the winner at 11.26am EST on Saturday 7 November, four days after election day.
On its race callers, the AP adds: “They know before polls close how each county and congressional district in their state has voted in past elections, the state’s past results for voting by mail and early in-person voting, and the state’s history of counting votes – how many are counted after polls close and how many are counted in the days after.”
How do recounts work?
In many states, automatic recounts are enshrined in election law if the margin of victory in the initial results is below a certain threshold (whether that be fractions of a percentage point, or a margin of within a few thousand votes).
This is essentially to check for accuracy given the closeness of the race.
The key battleground state of Arizona, for example, mandates a recount if the vote margin between candidates is 0.5 per cent or less.
In some other states, a candidate can demand a recount themselves if they feel doing so could swing the result in their favour.
Georgia is among the states where this is the case, with recounts an option that can be requested by candidates if the vote margin is within 0.5 per cent.
Pennsylvania allows recounts in both instances, as well as if there are suspected errors or voter fraud.
Historically, however, recounts tend not to change results.
Between 2000 and 2019, recounts were held in 31 of the 5,778 statewide elections that occurred, with the outcome overturned just three times – all in instances where the margin of victory was less than 0.05 per cent.
In 2020, recounts backed by the Republican Party and the Trump campaign were conducted in counties in Wisconsin, Arizona and Texas and at a statewide level in Georgia.
All verified that Biden had won, as initially reported.
Meanwhile, back in the George W Bush versus Al Gore election in 2000, the US Supreme Court was forced to step in and decide the election in the Republicans’ favour by stopping a recount in Florida 35 days after election day.