The vice president breaks 50-50 ties. Predicted range covers 95% of simulations

Estimated Senate seats

Our model is updated every day, blending the latest data on polls and fundraising with “fundamental” factors like incumbency and each state’s partisan lean. Below is a chart over time of our best estimate of the most likely number of Senate seats each party will win, surrounded by a range of other plausible outcomes.

Senate simulations

Every day, our model explores 10,000 paths each Senate race could take. These simulations allow one party to do unusually well or poorly nationwide, and also provide appropriate uncertainty in each specific contest. The bars below display the probability of each of the two major parties winning a specific number of seats.

Win probability by race

Each state has two senators, but only a third are up for election at one time. Many of the 35 seats up for grabs this year are uncompetitive, so control of the Senate depends on a handful of hard-fought contests. The map below displays the party favoured to win each seat, and its estimated probability of victory.