Americans have two big questions as they head into another election with a deeply divided electorate: who will win, and when will they know it?

In 2020, election week replaced election night: Joe Biden wasn’t declared the winner until Saturday. This year, it could go either way. It may take as long as a week for the NBC News Decision Desk to project a presidential winner, or it could happen as early as Wednesday, even by Wednesday morning. 

The truth is the Decision Desk cannot know until election night which scenario will unfold, regardless of how carefully we have analyzed the polls, early vote, and other election-related data. The answer depends not only on how states count their votes but on the unknowable factor of how close the margins will be.

One thing is clear: The days of projecting a winner on election night itself are almost certainly over.

Projecting a presidential winner as early as Wednesday would require that the key battleground states, particularly Pennsylvania, are not essentially tied. There would need to be a large enough spread between the first and second place to be able to project a winner.

Races that are nearly tied, like the presidential race in Georgia and Arizona in 2020 (Joe Biden’s winning margins in these states were 11,779 and 10,457 votes, respectively), require essentially all the vote to be counted before NBC News’ Decision Desk can project a winner. This can take days.

But let’s go through the battleground states where Wednesday calls are at least possible.

How the critical ‘blue wall’ states count their votes — and how it’s different from 2020

Any path to winning the White House will likely go through the “blue wall” states of Pennsylvania, Michigan and Wisconsin. In 2020, Pennsylvania was the pivotal Electoral College state to call the presidency, and there is a decent chance it plays that role again. But in 2020, it took four days after Election Day for the NBC News Decision Desk to be able to declare a winner.

It may well happen much earlier this year. This is because 98% to 99% of the vote in Pennsylvania will likely be counted by Wednesday morning. 

How Pennsylvania counts its vote remains largely unchanged since 2020, but the process should be more efficient this year. Key counties like Allegheny (home of Pittsburgh) and Philadelphia have invested heavily in new voting machines and have added more personnel to help process ballots. Also, remember that this election is not being administered amid a global pandemic that required strict social distancing between election officials, slowing the count.

We expect several Pennsylvania counties to release large counts of early votes shortly after polls close, followed by the in-person Election Day vote. That would leave the early votes received on Election Day, along with provisional ballots, still to count on Wednesday.

If 99% of the total vote is counted quickly, a Wednesday projection is very possible in Pennsylvania, unless the race is razor tight. In 2022, we had about 90% of the vote counted in Pennsylvania when the NBC News Decision Desk projected Democrat John Fetterman as the winner of the state’s Senate race at 12:51 a.m. ET.

In Wisconsin and Michigan, the bulk of the vote could also be counted by Wednesday if past reporting patterns hold.

Based on those patterns, in Wisconsin, the amount counted by Wednesday morning should be over 99%. In Michigan, it should be more than 95%. An important note in Michigan: For the first time, municipalities with more than 5,000 residents can begin pre-processing absentee ballots — opening envelopes, verifying voter signatures and so on — several days before the election, which could lead to more efficient counting on election night.

On the other hand, the introduction of early in-person voting in Michigan could add some difficulty in quickly counting the vote. Regardless of these changes, both Michigan and Wisconsin count almost all of their votes quickly. So, unless the races are extremely close, there is a decent chance the NBC News Decision Desk would be able to make a projection sometime on Wednesday.

If the races are that close, however, it could take days or perhaps even a week, depending on the margins.

How the Sun Belt battlegrounds count their votes

Outside of the blue wall, the critical swing states of Georgia and North Carolina are among the best in the nation when it comes to efficiently processing and counting their votes.

These two states are also extremely good at making their data available to the public electronically. In Georgia, over 99% of the vote will be counted on election night. In fact, almost all the vote has been counted in recent past elections by 1 a.m. ET. However, Georgia was so close in 2020 that it took days to call the race.

North Carolina has a similar pattern in how it reports out the vote, with 99% of the vote counted by midnight in past elections. Still, any chance of an election night projection in either of these closely divided states depends on a wide enough spread between the two candidates.

The one electoral vote awarded to the winner in Nebraska’s 2nd Congressional District could also be pivotal in the path to 270. With no significant changes in how votes are counted in Nebraska, around 90% of the vote can be expected to be counted by Wednesday morning, which again could lead to a projection if there is enough spread between the candidates.

The last two battleground states, Arizona and Nevada, almost certainly won’t be called quickly. If the presidency comes down to one of these states, forget any thoughts of a Wednesday resolution.

In 2020, NBC News did not project a winner in Arizona until Nov. 12, nine days after Election Day. And unlike some other close states, it wasn’t just because the margin was so thin.

Typically, Arizona has as much as 20% of its vote still to count after election night —mainly late-arriving mail ballots. And there are very substantial differences between Republicans and Democrats in terms of who votes when (early versus on Election Day). This makes it nearly impossible to project a winner in Arizona on election night.

Nevada is a state that has a large amount of early voting, both absentee and in person, that is not counted on election night. In the past, nearly a quarter of the vote is still not counted by the Wednesday morning after Election Day.

Given that the state has been historically close in presidential elections, the probability of calling a close race with a large amount of uncounted vote is very low.

The bottom line: In Arizona and Nevada, it will likely take a few days, perhaps longer, to know the winner.