435 House seats, 35 Senate races: The numbers behind US midterms 2026

The 2026 US midterm elections, scheduled for November 3, will determine the balance of power in Congress during the second half of President Donald Trump's term. With all 435 voting seats in the House of Representatives and 35 Senate seats up for election, Republicans and Democrats are preparing for a crucial political contest. The outcome will influence legislation, congressional investigations, government spending and the Trump administration's ability to advance its agenda. From the Senate majority and the number of seats needed to change control to billions of dollars in campaign fundraising and spending, these 10 numbers explain the scale and stakes of the battle for Congress.

All 435 voting seats in the US House of Representatives are being contested in the November 3, 2026 midterm elections. The entire chamber faces voters every two years, making the House a central battleground for both parties. Control of the House determines which party leads committees, sets much of the legislative agenda and exercises congressional oversight over the White House. Even a small number of district-level victories can change the balance of power. The outcome will determine who controls the chamber when the 120th Congress convenes in January 2027.

Thirty-five of the US Senate's 100 seats are on the ballot in 2026, including 33 regularly scheduled elections and two special elections. Senators serve six-year terms, with roughly one-third of the chamber facing voters every two years. The contests span states with different political profiles, from traditionally Republican territory to competitive battlegrounds. Senate control matters because the chamber votes on legislation, confirms presidential nominees and plays a central role in national policy. For Democrats, gaining seats is essential to their effort to take control; Republicans are seeking to retain their majority.

Republicans entered the 2026 midterm cycle with a 53-seat Senate majority, compared with 47 seats held by Democrats and their caucus allies. That balance gives the GOP an advantage heading into the election, but it must defend its majority while Democrats target Republican-held seats. The contest is especially important because Senate control influences committee leadership, legislative negotiations and confirmation votes for presidential nominees. The final balance will depend on results across multiple states, including closely watched races in Ohio, Texas, Alaska and other battlegrounds. November's results will determine which party leads the chamber for the next Congress.

With Republicans holding 53 seats and Democrats and their caucus allies holding 47, Democrats need a net gain of four seats to secure a Senate majority. That requires flipping Republican-held seats while protecting their own vulnerable contests. Winning four races alone would not be enough if Democrats also lost seats elsewhere. The arithmetic explains why national parties are concentrating money, advertising and campaign visits on a relatively small number of competitive states. Senate control affects the legislative agenda, committee leadership and the confirmation of presidential nominees. The results will show whether Democrats can change the chamber's balance or Republicans can preserve their majority.