How many electoral votes are needed to win?

A presidential candidate needs 270 electoral votes to win the presidency, which is a majority of the 538 total electoral votes. The 270 majority threshold is set by Article II, Section 1 of the Constitution, as modified by the 12th Amendment, which requires the person elected President to receive a majority of all the electors appointed. Since the total number of electors is 538, a majority requires 270 votes.

Falling short of 270 has dramatic consequences. If no candidate receives a majority of electoral votes, the election is decided by the U.S. House of Representatives under the 12th Amendment. Each state delegation in the House casts one vote, and the candidate with the most state delegation votes wins. The selection is made from the top three candidates in electoral votes. This contingent election procedure has happened twice in American history: in 1800, when Thomas Jefferson and Aaron Burr tied in electoral votes and the House chose Jefferson after 36 ballots, and in 1824, when no candidate won a majority and the House chose John Quincy Adams over Andrew Jackson. Andrew Jackson, who had won the most electoral votes (but not a majority), and the most popular votes, called the result a corrupt bargain and went on to win the 1828 election.

The 270 threshold shapes presidential campaign strategy. Candidates focus their time, money, and attention on states where the result is in doubt, the so-called swing states. Recent swing states have included Pennsylvania, Michigan, Wisconsin, Arizona, Georgia, Nevada, and North Carolina. Other states are reliably Democratic (such as California, New York, and Massachusetts) or reliably Republican (such as Texas, Tennessee, and most of the South and Mountain West) and receive less candidate attention because the outcome is largely predictable.

The 270 threshold also explains why a candidate can win the presidency without winning the most votes nationwide. Because most states use winner-take-all rules, a candidate can run up huge margins in some states while losing many other states by small margins. The system rewards geographic distribution of votes, not raw popular vote totals. This has happened five times in American history: in 1824, 1876, 1888, 2000 (when George W. Bush won), and 2016 (when Donald Trump won).

Reform proposals to replace the Electoral College with direct popular election have not advanced significantly, in part because such a change would require a constitutional amendment ratified by three-fourths of the states.