Right now, there are 54 Republicans, 45 Democrats and one independent in the U.S. Senate. There are 34 seats up for grabs in 2016 -- Republicans hold 24 and Democrats 10. Democrats will need to gain four or five seats to take control (if Hillary Clinton is elected president, Democrats would need only four seats because Vice President Tim Kaine would break any ties).
Only 12 Senate races and 48 House races are considered even potentially competitive. The “expected” bar shows both current calls and races that are considered “safe” Democratic and Republican seats. Independents are grouped according to their likely caucus affiliation (in the Senate, Bernie Sanders of Vermont and Angus King of Maine both caucus with the Democrats).
Throughout the night, you’ll be able to monitor party control of the House and Senate as races are called. Here’s what the scales look like now: