US election: Donald Trump v Joe Biden, live results

The interactive map shows the race for president and Congress in real time. AP Graphic

Follow the whole US election in real time on our interactive map. Click on the buttons at the top to choose the contest you want to follow, such as the presidency, Congress and the Senate. Then click on a state or even a county for a more detailed breakdown of the results.

Follow the US Congress race in real time here. All 435 seats in the House of Representatives and 35 of the 100 seats in the Senate are up for re-election.

Will Donald Trump defeat Joe Biden to win a second term in the White House? Everything we know about the 2020 presidential election so far.

The 2020 US election is finally here. But the coronavirus pandemic has thrown many aspects of the race into uncertainty.

The virus has already dramatically affected the running of the election, including the chaos caused by Donald Trump being diagnosed with Covid-19.

It is also unclear how election day will look, given the risk of catching the virus by voting in person.

A record number of people have already cast their ballots by post. Election experts suggest this could mean the result may not be declared on election night, but may take several days - or even weeks - to emerge.

With the coronavirus pandemic expected to affect public life well into next year, the 2020 election is likely to go down in history as one of the most unconventional US presidential races ever held.

Despite the uncertainty, some aspects of the election process are enshrined in the US constitution.

Here is what we know about how the race will play out.

The US Election in a nutshell

The American presidential elections are always held on the Tuesday after the first Monday in November.

Americans vote for people called "electors" in their state who are supporting the candidate they want to become president - this process is called the electoral college.

The more people who live in a state, the more electors there are for that state. So California for example, with a population of 38.8 million, has 55 votes - Delaware, (population 936,000), has just three.

There are 538 electors in total, corresponding to the 435 Representatives (Congress men and women) and 100 Senators, plus three additional electors from the District of Columbia. The Constitution prohibits any federal official, elected or appointed, from being an elector.

The candidate with the most electors wins all the state's electoral college votes and the first candidate to win enough states to get to 270 electoral votes is elected as president.

How does the electoral college work?

All 50 US states and Washington DC have a set number of "electors" in the electoral college – roughly proportionate to the size of each state.

Each state gets at least three electoral votes because the amount is equal to its total number of Senators and Representatives in the US Congress. Washington DC also gets three electoral college votes, meaning a total of 538 electors form the Electoral College.

California, the largest state, has 55 electoral votes, Texas, the next largest, gets 38. New York and Florida have 29 each.

All but Maine and Nebraska use a winner-takes-all system, so if you win the most votes in a state, you take its entire haul of electoral college votes.

To become president either candidate needs to win a majority of the 538 electors - i.e. 270 electors.

Although the Constitution does not dictate that electors follow the popular vote, many US states have laws requiring them to do so. These laws have been challenged by electors voting for someone else on occasion, but in July, the US Supreme Court ruled that electors must follow the popular vote in states that have such a law.

The electoral college system does usually reflect the popular vote – presidents have won the electoral vote while losing the popular vote just five times in US history. The most recent instance was in 2016, when Donald Trump won the electoral college but Hillary Clinton, his Democratic opponent, won the popular vote.

Who can become president?

The President of the United States can be a man or a woman of any race or any religion, but they must:

• Be at least 35 years old
• Have been born in the US
• Have lived in the US for at least 14 years

The rules also state that one person can be in the job for a maximum of two terms. (The only exception to this was Franklin D Roosevelt, who was elected for a special third term at the height of World War II.)

How does US election voting work?

The presidential election vote is a simple choice between candidates from the Democratic Party and the Republican Party. Occasionally a third party candidate will enter the race, like Kanye West this year, but it is quite rare for them to gain traction or make a significant impact.

The two main political parties hold primaries and caucuses across the country during an election year to select who they want to represent them on the ballot.

The Democratic and Republican candidates are then formally selected and announced during their parties' summer conventions.

The US election system itself is far from straightforward. That is because when America's founding fathers created the system in 1787, there was no way a presidential candidate could mount a national campaign – and there was little in the way of national identity.

The founding fathers chose not to elect US presidents by direct popular vote over fears that larger and more populous states could have an outsized role in deciding the winner.

The system of electors, based loosely on the Roman Catholic College of Cardinals selecting the Pope, was chosen with the theory that the most knowledgeable and informed individuals from each state would select a president on merit, disregarding state loyalties.

So when Americans cast their vote on November 3, they technically vote for "electors", not the candidates themselves. The electors are state officials or senior party figures, but they are not usually named on the ballot.

Each elector casts one vote after the general election for one of the two candidates. The newly elected president and vice-president will then be inaugurated on January 20, 2021.