Are you trying to work who will be US president when you wake up tomorrow morning?
The first exit polls are expected at midnight GMT, with east coast results then starting to arrive.
The earliest a candidate can be declared victorious is around 4am GMT.
In 2012, Obama had it clinched by 4.30am, but it could be much tougher to call this time round.
So if you can’t stay up to the wee hours, here are a few of things to look out for early on:
1.Virginia
President Obama won Virginia twice. Most notably in 2008, it was taken as an early sign that he would defeat rival John McCain. If Clinton does poorly here – despite a lead in the polls – it could be a sign she is in for a hard night.
2. New Hampshire
The earliest ballots cast here saw Clinton pip Trump to the post, by four votes to two. The generally well-educated state is traditionally Democrat – but is also very white. If Clinton doesn’t do well here, it could spell trouble. It is also normally one of the first states to declare a result.
3. Georgia
This state should be a sure thing for Republican Trump. But opinion polls have suggested Clinton is closing in in the traditionally red state. With a large African American population, a high Democrat vote here will let Clinton breathe a sigh of relief – and will jitter Trump’s nerves (if that’s possible).
4. Florida
In contrast to Clinton, if Trump fails to win Florida, his chances of reaching the necessary Electoral College votes are pretty much nil. Early signs here will therefore be a key bellwether for whether he can actually make it over the line at all. Reports suggest Hispanic voters are turning out in large numbers – an eventuality that most commentators agree is likely to hurt the Republican.
5. North Carolina
A state Romney turned red in 2012, Trump needs a victory here. Campaigning here from both sides has been frequent and grand, with polling suggesting a tight race. If the Republican loses out here, he will have an even tougher fight to reach the 270 Electoral College votes.
6. Ohio
So goes Ohio, so goes the nation. The old phrase will be less true in this election, but it is still worth watchingdere. With a large white working-class population, however, it is thought Trump could clinch the state. Polls are tight – a strong showing for either candidate could be an indication of how the night will go.
7. New York
Not a swing state by any means, but it is unusually the back yard of both candidates. The Big Apple should back Clinton in overwhelming numbers. But what if New Yorkers are holding a secret heart for Trump?