If you ever think that just one vote in a sea of millions cannot make much of a difference, consider one of the closest elections in U.S. history.

In 2000, Al Gore narrowly lost the Electoral College vote to George W. Bush. The election came down to a recount in Florida, where Bush had won the popular vote by such a small margin that it triggered an automatic recount and a Supreme Court case (Bush v. Gore). In the end, Bush won Florida by 0.009 percent of the votes cast in the state, or 537 votes. Had 600 more pro-Gore voters gone to the polls in Florida that November, there may have been an entirely different president from 2000–2008.

Your vote may not directly elect the president, but if your vote joins enough others in your voting district or county, your vote undoubtedly matters when it comes to electoral results. Most states have a “winner take all” system where the popular vote winner gets the state’s electoral votes. There are also local and state elections to consider. While presidential or other national elections usually get a significant voter turnout, local elections are typically decided by a much smaller group of voters.