When will we know the election results? What is worth knowing about vote counting.

In 2020, the Associated Press and other news outlets determined that Joe Biden had won the presidency four days after the election. The swing states that took the longest back then may be slow again this year: Pennsylvania, Arizona and Nevada. If the race is close, other states could join the list.

In addition to legal restrictions on when officials can count absentee ballots, long lines at polling places at the end of the day could also slow the count because voters who line up at closing time can still vote.

In addition, there are ballots from overseas and military voters that sometimes arrive after Election Day, along with provisional ballots cast by voters whose eligibility is in question. In a very close election, the result is unclear until the last votes are counted.

Here’s a look at the seven battleground states and when you can expect the results.

Pennsylvania

In 2020, the Associated Press called the state for Biden on the Saturday after Election Day. Election officials expect vote counting to take several days again this year.

Unlike many states, officials there are not allowed to begin processing absentee ballots until 7 a.m. on Election Day. The process is labor-intensive. Workers must check that voters have provided all the necessary information, then remove the ballots from the envelopes, unfold them, check for damage, and insert them into the voting tabs.

Pennsylvania has arcane rules that could lead to ballot challenges. Absentee ballots must be placed in a secrecy envelope, which must then be placed in a mailing envelope. Envelopes must be properly dated. In case of errors, votes may not be counted.

Arizona

Four years ago, Fox News and the Associated Press called Biden to Arizona on election night, a move others said was premature. Most networks waited several days to determine whether Biden would win the state. This time, unofficial results may take that long again.

Arizona allows election officials to process early ballots as soon as they are received, but many voters wait until Election Day to return them.

There are concerns that vote counting in Arizona could take even longer this year because the ballot is unusually long. In Maricopa County, the state’s most populous county, races and ballot questions take up two pages rather than one, meaning voters and clerks will have to put twice as many sheets of paper into vote-counting machines this year. This increases the risk of paper jams that slow down vote counting.

Nevada

In 2020, the Associated Press called Nevada on Biden’s behalf on the Saturday after Election Day.

Voting in Nevada is mostly by mail, and Secretary of State Cisco Aguilar, a Democrat, has advised counties to start tabulating those ballots as soon as polls open on Election Day, rather than after they close as they have in the past.

On Election Day, after the last voter has cast their ballot, the Secretary of State will give counties the green light to release the total results of all in-person ballots cast and all absentee ballots received before that date. Only ballots submitted in person on Election Day and mail-in votes that arrive the same day or later will remain. Constituency figures will begin to appear on Tuesday evening, but full information will likely not be released until the end of the week.

Most states require ballots to be returned by Election Day, but Nevada counts absentee ballots without a postmark that arrive up to three days after Election Day and those postmarked up to four days after Election Day. This creates uncertainty as to when the results will be known, especially in a close election. The second-highest day for receiving absentee ballots in Nevada is typically the day after the election.

Georgia

Networks called Georgia for Biden on the Friday after the 2020 election. Election officials expect the count to go faster this year.

Election officials can process absentee ballots as soon as they are received and begin counting them at 7 a.m. on Election Day.

One hour after polls close on Election Day – which is scheduled for 7 p.m. ET – state election officials plan to release counts of all absentee and early ballots processed. Early voting has been extremely popular this year, with over half of registered voters having already cast their ballots. Officials estimate that most of the county’s Election Day data will be released before midnight Tuesday. They will also publish the total number of votes cast that day, which will inform the public how many votes remain to be counted.

It will take longer for a few stragglers, likely including Fulton County, the state’s largest jurisdiction, which is administering a new counting center this year.

Michigan

Michigan was called for Biden the day after Election Day. This year, Secretary of State Jocelyn Benson, a Democrat, said she expected unofficial results for the state by the end of Wednesday.

This year, large and medium-sized communities began processing their absentee ballots last week; communities with fewer than 5,000 residents can hear them on Monday. All jurisdictions tally votes on Election Day.

In 2022, Michigan approved an in-person early voting measure. Those who vote this way enter their ballots into the tabulators as they would on Election Day. This means less work for officials on Election Day and should speed up the counting.

Wisconsin

In 2020, counting in Wisconsin ended early the morning after the election, and the Associated Press called the state on Biden’s behalf that afternoon.

Election officials cannot count early absentee or in-person ballots until Election Day, which could lead to counting delays.

Milwaukee, a Democratic stronghold and the state’s largest city, is expected to be one of the last cities in the state to report full results because it needs time to count pre-election and mailed votes at a central counting facility. Milwaukee’s elections director expects complete, unofficial results to be announced around midnight. Several other jurisdictions in the state could report their results later.

North Carolina

The state has historically reported most results relatively quickly and could provide early clues as to how Trump and Harris will fare nationally.

The vote counting process in North Carolina is faster because election officials can remove absentee ballots from envelopes and enter them into tabulators weeks before Election Day. They tally results on Election Day but cannot announce them until polls close at 7:30 p.m. EST.

Election officials first provide totals for mail-in ballots, then totals for people who voted early in person or on Election Day.

Due to damage from Hurricane Helene, some counties will have to report their results to election offices instead of providing them with computer memory cards. This may slow down the announcement of results in some districts.