2026 Election BettingBlue Wave Odds 2026: Will Democrats Get at Least 218 House and 49 Senate Seats?

A "blue wave" in these markets has an exact meaning: Democrats with at least 218 House seats and at least 49 Senate seats. The House half got a lift on October 9, when the Cook Political Report moved 18 House races toward Democrats and put its expected Democratic total at 224 to 234 seats, above 218.

Compare House control odds for the House-only outcome.

That leaves the Senate half. Democrats hold 47 seats now, so 49 means a net gain of two, short of the four they need for a majority.

The newest polls in two Republican-held seats are close: Texas was tied at 45% in a UMass Lowell poll released October 8, and Maine's Collins and Jackson held their third debate on October 13.

Traders think both halves are likely. Kalshi's blue wave betting market last traded at 80¢, and Polymarket's sat at about 84.5¢. The two prediction market apps count seats differently (see below), so each has its own table and they aren't averaged. Neither is the House odds multiplied by the Senate odds. The live tables above update through the day to give you the latest odds and a comprison of what traders think will happen on Nov. 3.

Latest updates

• October 14, 2026 (checked about 10:20 p.m. Eastern): Kalshi's blue wave market last traded at 80¢ (79¢ bid, 80¢ ask). Polymarket's had an 84.5% midpoint (84¢ bid, 85¢ ask). These are snapshots; the tables above show the current prices.
• October 13, 2026: a NewsNation and DDHQ poll taken October 5–9 had Democrats ahead 49% to 42% on the generic ballot.
• October 9, 2026: Cook moved 18 House ratings toward Democrats and put its expected Democratic total at 224 to 234 seats.
• October 8, 2026: UMass Lowell's Texas poll had Talarico and Paxton tied at 45%.

What counts as a blue wave in prediction markets

Both prediction sites use the same bar: at least 218 House seats and at least 49 Senate seats for Democrats. Both halves have to happen. A House majority with 48 Senate seats is a No.

Forty-nine Senate seats is not a majority. A blue wave on this definition can still leave Republicans running the Senate.

Use the midterm hub’s Senate control odds for the separate question of which party wins the chamber.

The balance-of-power combinations separately price which party controls each chamber.

The two venues count at different times, so the same election can settle them differently; see below.

What matters for this market

• Two Senate pickups: Democrats need a net gain of two. Maine, North Carolina and Texas are among the seats where polls are close or moving their way.

• Holding their own seats: Any Democratic seat lost raises the number of pickups needed.

• The House margin: Cook's 224 to 234 is a forecast, not a floor: the House half still fails if Democrats end up below 218.

Key dates

• Tuesday, November 3, 2026: general election.
• February 1, 2027: Kalshi counts the seats Democrats hold.

How the blue wave markets settle

Kalshi's blue wave market (KXBLUEWAVECOMBO-27FEB) asks whether Democrats hold 218 or more House seats and 49 or more Senate seats, counted on February 1, 2027. The election is November 3, 2026.

Polymarket's "Blue wave in 2026?" market uses the same 218 and 49 bar but counts the seats won in the 2026 election rather than the seats held in February. A vacancy or party switch after Election Day could settle the two differently, which is why their prices aren't averaged.

Polymarket US lists a blue wave market with the same bar, but the site can't show its prices yet. A separate "blue tsunami" market with higher thresholds is a different question and isn't on this page.