Final answer:
The number of electors each state receives in the Electoral College is based on its total congressional delegation: two senators, plus the number of its House representatives, which is determined by the state's population as assessed by the U.S. Census every ten years.
Step-by-step explanation:
The number of electors that a state gets in the Electoral College is equal to the total number of senators (always two) and representatives in the House of Representatives that the state has in the U.S. Congress. This is outlined in Article II, Section 1 of the Constitution. The number of representatives a state has is determined by its population, which is assessed every ten years through the U.S. Census as mandated by Article I, Section 2 of the Constitution.
However, although the number of state representatives may change with population shifts, the total number of representatives has been fixed at 435 since the Permanent Apportionment Act of 1929. Additionally, Washington, DC is granted as many electors as it would have if it were a state, although it does not have voting representation in Congress. In practical terms, the Electoral College has 538 electors, and a majority of 270 electoral votes is needed to win the presidency. It is worth noting that most states utilize a 'winner-take-all' approach to allocating their electoral votes, but Nebraska and Maine use a proportional system based on congressional district outcomes.