Four years after 2020 gave us an “election week,” voters are heading to the polls wondering: How long will it take for states to count their ballots this year?

Since the last presidential election, some dynamics have changed: many voters have returned to voting in person after the Covid pandemic, and many states have rewritten their laws to allow election officials to begin processing mail-in ballots before Election Day . These two changes are expected to speed up tabulation, but it could still take days for a full picture of the election results to emerge.

Close elections take longer for news organizations like NBC News to call because winners can be determined by absentee and provisional ballots, which can take days for election officials to process and count.

Follow live updates on the 2024 elections

Mail-in absentee ballots take more time to process than votes cast in person because election workers must verify voters’ identities and remove them from envelopes.

And provisional ballots are cast by people whose election workers could not immediately confirm their eligibility to vote when they cast their ballots. These ballots are separated from eligible ballots until officials can investigate whether the votes are valid.

As we get closer to Election Day, here’s a look at the rules for how the seven key battleground states likely to influence the presidential election can count those ballots.

Arizona

Ballots by post: Arizona voters typically vote by mail, so if ballots are dropped off at the last minute, counting could take longer. State officials say vote counting could take 10 days although mail-in votes may be counted once received, according to Arizona’s secretary of state.

Provisional ballots: Provisional ballots, which require additional review by officials or documents from voters, can be counted up to 10 days after the election under state law.

Georgia

Ballots by post: Georgia will begin processing mail-in ballots on Oct. 21, and they can be delivered until polls close on Election Day.

Provisional Ballots: Voters have three days to prove their identity or confirm their identity after casting provisional ballots, but results are expected soon.

Michigan:

Ballots by post: Larger jurisdictions in Michigan can begin processing mail-in ballots on Oct. 28, allowing election officials to take a much-needed early step in verifying mail-in ballots. Mail-in ballots must be received before the polls close on Election Day.

Provisional provisions: Clerks have until Nov. 12 to process provisional ballots.

Nevada

Ballots by post: Mail-in ballots must be postmarked by Election Day and received by November 9. Election officials can begin processing them as soon as they receive them.

Provisional ballots: Voters have three days after Election Day to prove their residency and identity, if necessary. If their signatures don’t match the signatures on file for their mail-in ballots, they have until November 12 to “cure” their ballots.

North Carolina

Ballots by post: Mail-in ballots must be received by Election Day and will be partially processed in October.

Provisional ballots: Voters who were unable to show sufficient identification at the polls have until November 14 to bring the necessary identification to election officials. Election officials can process other provisional ballots until counties begin collecting results on Nov. 15.

Pennsylvania

Ballots by post: Election officials must receive mail-in ballots before the polls close on Election Day. Processing begins at 7 a.m. on Election Day, making the state one of the last battlegrounds to verify signatures and personal information on ballots.

Provisional ballots: County boards must review and decide whether provisional ballots should be counted within a week of the election.

Wisconsin

Postal ballots: Ballots must be received no later than Election Day. Processing will begin at 7 a.m. local time on Election Day, making Wisconsin the last state to begin processing ballots.

Provisional ballots: Voters have until Friday after the election at 4 p.m. to provide necessary documentation, such as ID, to election officials to ensure their ballots will count.