Last updated 11/4/24

AllSides' final 2024 Senate & House election forecast is out. View the latest news, polls, and examples of media bias around the the 2024 House Elections and 2024 Senate Elections on AllSides.

AllSides is tracking the odds of each race for the U.S. Senate & House in the 2024 elections.

Republicans Currently Have an 88% Chance of Taking the Senate

We're currently projecting that Republicans will hold 52 seats and Democrats will hold 48 seats in the Senate after the election.

Of the 34 Senate seats up for election, 15 are Solid Democrat, 2 are Likely Democrat, 3 are Lean Democrat, 1 is a toss-up, 0 are Lean Republican, 4 are Likely Republican, and 9 are Solid Republican.

The toss-up Senate race is in Ohio, where Republican businessman Bernie Moreno is taking on the Democratic incumbent Sherrod Brown.

Of the 66 seats not up for election, 28 are currently held by Democrats or Independents that caucus with Democrats, and 38 are held by Republicans.

Generally, a total of 51 seats are needed to control the Senate. In the case of a 50-50 split, the majority is given to the party that controls the presidency, as the Vice President of the United States has a tiebreaking vote.

RELATED: See Who’s Ahead in AllSides’ 2024 Presidential Election Model

Republicans Currently Have a 57% Chance of Taking the House

We're currently projecting that Republicans will hold 221 seats and Democrats will hold 214 seats in the House after the election.

All 435 House seats are up for election. As of our final update, 167 seats are Solid Democrat, 29 are Likely Democrat, 11 are Lean Democrat, 20 are toss-ups, 8 are Lean Republican, 23 are Likely Republican, and 177 are Solid Republican.

How This Model Works

The AllSides 2024 Senate & House Election Forecast Model takes into account national and state horse race polling, approval polling, history of past elections, and more to estimate the percentage vote share of each candidate in the 2024 presidential election and the probability that they will win a district, state, and the electoral college.

The data visualizations indicate the probability of each candidate winning a state and how many electoral college votes are predicted to go to each candidate. “Solid” states have a 90% or greater probability of going to a candidate of the indicated party, “Likely” have 70-89.9%, “Lean” have 60-69.9%, and “Toss-Up” states have less than 60% probability of going to either candidate.

To develop an expected vote share for each candidate, the model incorporates the inherent state lean (ISL), approval rating, primary results, and polling averages. We created the ISL using the presidential, senatorial, and gubernatorial general election results from 2012 to present day to determine what the expected vote share in each state would be in an election where the popular vote was equal between the Democrat and Republican nominees.

For the Senate Model specifically, Morning Consults’ approval ratings of every U.S. Senator up for reelection, in combination with an incumbency bounce, likely voter weight, and allocation of undecided voters were used to determine the expected vote share for every incumbent and challenger. The primary election results of 2024 were used to determine the expected vote share turnout for the candidates.

The Senate model takes into account the odds produced by the AllSides 2024 Presidential Model of either the Democrat and Republican party winning the presidency. In the event of a 50-50 split in the Senate, the Vice President, as part of the winning presidential ticket, can cast the tie-breaking vote.

For the House Model specifically, the model incorporated FiveThirtyEight’s partisan lean and Daily Kos’s 2020 presidential vote on the 2022 U.S. House district map to determine the ISL for each U.S. House district.

To determine the expected vote share per candidate in each state, we used polling averages from FiveThirtyEight and RealClearPolitics, in combination with a likely voter weight and allocation of undecided voters. The largest weight is given to polling averages, then ISLs, approval ratings, and lastly, primary results received the least weight. When these data were not applicable, they were not used. As the general election date gets closer, the weight of polling averages will increase. The combination of the data determined the expected vote share for each candidate. With the numbers produced from the expected vote share, the model uses a normal distribution to produce the probability of a candidate receiving a larger vote share than their opposing candidate.

The model includes an uncertainty factor that will gradually decrease over time and reach 0 on the date of the general election. 

Independent candidates have been added to states where there has been official confirmation about their ballot access, and will be added to more states as the official requirements of each state have been reached.

Election forecasting models aren’t perfect predictors of election outcomes, but they can help paint a picture of what the results may look like in November.