The presidential election on 5 November is set to be the tightest race since at least 2000.
Just days away, it is so close, that Kamala Harris and Donald Trump are practically tied in a dead heat, according to the latest polls.
But the US election is not all about who wins the most votes, it’s about who wins in the right states.
How does the US election work?
If we add up the votes in “safe” states that the candidates probably don’t need to worry about so much, Harris is on 225 electoral college votes and Trump on 219, in their race to 270.
Of the 94 votes left in the eight crucial swing states where the races are tight, Harris needs 45 to win the presidency and Trump needs 51. Harris is currently leading in more of these.
Read about the latest developments in the US election in our live blog
But the leads are all narrow – within the margin of error. Harris would become president if she wins where she is currently leading, as well as either one of the two states where there’s less than one point in the race. Trump would need to win both tied states, as well as the two where he’s ahead.
In the betting odds, Trump and Harris have regularly exchanged narrow leads throughout the campaign, but in recent weeks Trump has accelerated into his largest lead since Harris became the candidate.
The percentage refers to the candidates’ overall chance of winning, by whatever margin, not an implied vote share or electoral college split.
Predict who you think will win in each swing state and we’ll tell you who the president will be if you’re right.
Battleground states
We can already be fairly confident of the result in lots of states. California and New York for example have voted Democrat at every election for the past 30 years.
Texas is the same the other way around – despite long-prophesised theories that the increasing Hispanic population would eventually turn the Lone Star State blue, they haven’t voted for a Democrat since Jimmy Carter in 1976, almost 50 years ago. Only five states changed hands in 2020.
That’s why those eight blocks of votes that could go either way are so very important.
If Trump doesn’t win in Pennsylvania, his route to victory becomes increasingly narrow – he would need to win at least four of the six biggest remaining states.
If he does win there, however, he can become president with just two others.
The single electoral vote in Nebraska 2nd could make all the difference if other states go a certain way.
If Trump wins Pennsylvania and Michigan back and the other results stay as they were in 2020, he would be stuck on 269 – Nebraska 2nd would take him over the line.
What happens if it’s a tie in the electoral college?
How does the US election work?
Each of the fifty states, plus Washington DC, holds their own vote for president which is independent from the others.
Each state is worth an amount of “electoral college votes” – effectively points – related to the population of the state.
California, the most populous US state, has 54 electoral college votes representing their 39 million population.
Wyoming, the smallest US state, has three electoral college votes representing their 600,000 population.
There are 538 “points” in total. To become president, a candidate must get to 270 (more than half). It doesn’t matter what combination of states gets them there, but some routes are easier than others.
In most states – all except Nebraska and Maine – the winning candidate in a state gets all of the electoral votes available.
So if Donald Trump was to win Florida by a single vote, he would get all 30 of their electoral college votes, the same as if he got 100% of the popular vote there.
In Nebraska, two votes are allocated to who wins the state overall, and one each to the candidate who wins in three districts of Nebraska – making five overall. It’s the same in Maine but there are only four electoral college votes up for grabs there, so its other votes are split across two districts rather than three.
Who is the people’s favourite?
Sometimes it’s not about policy but just about whether you like one candidate more than another.
Americans are more likely to find Donald Trump unfavourable than favourable, although he had been more popular than Harris before she became the candidate.
Since then, Harris’s favourability ratings have risen, but have hovered around zero – meaning just as many people find her unfavourable as favourable. In recent weeks, like the national polls, these ratings have converged closer and closer.
As the election approaches, keep an eye on all these trackers to see the polls and betting markets’ predictions evolve, and what they reveal about where the race to become president is going.
And you can follow our live coverage here on Sky News throughout the night as exit polls start coming in from across the US.
The Data and Forensics team is a multi-skilled unit dedicated to providing transparent journalism from Sky News. We gather, analyse and visualise data to tell data-driven stories. We combine traditional reporting skills with advanced analysis of satellite images, social media and other open source information. Through multimedia storytelling, we aim to better explain the world while also showing how our journalism is done.