How many Senate seats are up in 2026? Senate seat odds

Last updated: October 22, 2026

Thirty-five Senate seats are up for reelection in the November 3, 2026 midterms. Republicans hold the Senate 53-47, and Democrats need a net gain of four seats to win a majority. As of 11:44 a.m. ET on October 22, 2026, Kalshi traders give Democrats a 68% chance of winning control.

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On paper, the 2026 Senate map started out favoring Republicans. They entered the cycle with a 53-47 majority, and many of the seats Democrats would need to flip are in states that usually vote Republican. Because Vice President JD Vance breaks 50-50 ties, Democrats need a net gain of four seats, not three, to win the majority.

Republicans are also defending far more seats this year, and several of their races have turned competitive. Below, we list every Senate seat up in 2026 and pair the most competitive races with live odds from Kalshi's prediction markets.

For key dates, registration deadlines and prediction market odds heading into Election Day, see Kalshi's guide to when the 2026 midterm elections are.

Thirty-five Senate seats are up for election in 2026. That number has two parts:

The other 65 senators aren't on the ballot this year. Whichever party wins more of these 35 races will decide who controls the Senate.

Republicans are defending 22 of the 35 seats on the ballot, and Democrats are defending 13.

All 35 Senate races in 2026 are below:

Source: Cook Political Report

A handful of the 35 races will likely decide control. The groups below are based on Kalshi odds as of 11:44 a.m. ET on October 22, 2026: a race is a tossup when neither side is above 70%, and leans toward a party when that party is above 70%. Forecasters like the Cook Political Report rate some of these races differently, so each race also shows Cook's rating as of October 20.

Which 2026 Senate races are the most competitive? By Kalshi odds, the closest races are Iowa, Kansas, Maine, Texas, Michigan and Ohio. Cook also rates all six as toss-ups, along with Alaska.

Kalshi's Senate control market trades Yes and No contracts priced in cents. A contract pays $1 if that party wins the Senate and $0 if it doesn't, so its price reads as the market's implied probability.

Kalshi also lists a market for each Senate race, and those settle the same way. Each candidate’s contract pays $1 if that candidate’s party wins the seat and $0 if it doesn’t, so a candidate trading at 68¢ has roughly a 68% market-implied chance of winning. Race prices move as traders react to polls, debates, fundraising and candidate news

Kalshi Senate odds of some of the key races. Prices as of 11:44 a.m. ET, October 22, 2026

*Alaska's market is priced by party, not by candidate.

At these prices, traders favor Democrats to flip North Carolina, Alaska, Ohio, Texas and Maine, which would be more than the four they need if they also hold Michigan. These probabilities are not forecasts. They reflect current trading and can shift quickly before Election Day.

Thirty-five Senate seats are up in 2026: 33 regular races plus special elections in Florida and Ohio. Republicans are defending 22 of those seats and Democrats 13.

Current prediction-market odds point to Democrats' clearest path running through North Carolina and a handful of Republican-held tossups such as Ohio, Texas and Maine, while holding Michigan. Kalshi traders price Democratic control at 68% as of October 22, 2026, but several of those races remain close enough to swing the result.

To follow the odds through November 3 and as results come in, track Kalshi's Senate control market and the individual race markets on the 2026 midterms page.

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