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2026 Midterm Election Odds Democrats are favored to win both chambers

Democrats are strong favorites for the House. The Senate is closer, and the 51st seat runs through Ohio.

Who wins the Senate?
65%Democrats

About 2 in 3▲ Up 2 pts this week

Kalshi shows a last trade; Polymarket shows a price to buy. $100 on Polymarket at the ask pays $153 if correct, before fees.

Who wins the House?
93%Democrats

About 19 in 20Unchanged this week (Kalshi)

Prices to buy now. $100 on Kalshi at the ask pays $108 if correct, before fees.

Market moves

Biggest moves, last 7 days

Kansas SenateDemocrat · Kalshi
30% → 36%
+6 pts
Ohio special SenateBrown (D) vs. Husted (R) · Kalshi
58% → 63%
+5 pts
Texas SenateTalarico (D) vs. Paxton (R) · Kalshi
60% → 64%
+5 pts

See all 14 markets →

Change in percentage points over 7 days, from daily closing prices to the latest observation (Oct 4, 10:02 AM ET).

Race explorer

All 35 Senate races

Chance the Democrat wins each race, from Kalshi, closest races first.

Kalshi prices to buy; a stale quote shows its last price instead. “Buy GOP” buys No on the Democratic contract, except in Nebraska, where an independent is running. Tap a price to open that race’s market.

All 35 2026 Senate races on Kalshi, closest first, Oct 4, 10:02 AM ET
RaceDem chance7 daysBuy DemBuy GOPSources
Iowa Stale quoteTurek (D) vs. Hinson (R)44%
At last trade, $100 returns $229
+1 ptsDem43.5¢GOPStaleSources & contracts›Sources & contracts›
Maine Stale quoteJackson (D) vs. Collins (R)59%
At last trade, $100 returns $170
−1 ptsDem58.5¢GOPStaleSources & contracts›Sources & contracts›
Ohio 51st seatBrown (D) vs. Husted (R)63%
At last trade, $100 returns $160
+5 ptsDem62.5¢GOPStaleSources & contracts›Sources & contracts›
TexasTalarico (D) vs. Paxton (R)64%
$100 on GOP at the ask pays $270
+5 ptsDem65¢GOP37¢Sources & contracts›Sources & contracts›
Kansas36%
$100 on Dem at the ask pays $277
+6 ptsDem36¢GOP65¢Sources & contracts›Sources & contracts›
MichiganEl-Sayed (D) vs. Rogers (R)72%
$100 on GOP at the ask pays $344
–Dem72¢GOP29¢Sources & contracts›Sources & contracts›
Alaska Stale quotePeltola (D) vs. Sullivan (R)73%
At last trade, $100 returns $136
+3 ptsDem73¢GOPStaleSources & contracts›Sources & contracts›
New HampshirePappas (D)86%
$100 on GOP at the ask pays $666
+1 ptsDem87¢GOP15¢Sources & contracts›Sources & contracts›

Source: Kalshi / Polymarket via DeFi Rate, observed between Oct 4, 8:18 AM and 10:01 AM ET. Some quotes are stale: they weren’t observed recently and may have moved, so they show their last price and aren’t offered as a price to buy. Each race’s sources show when.

The evidence

Where the numbers come from

Every venue we track, the range they span, and how our figure sits inside it. Open any source to see the contract, bid and ask, and quote age.

Senate control · every source we trackobserved 10:02 AM ET
55%60%65%70%Gemini60PM US63.7Polymarket64.5Kalshi64.5RTWH model68.9Our figure 65%
● live venue, in our figure○ stale or editor-observed, shown but not averaged◇ forecast model, not a market▮ shaded band = range across live venues
Senate control since Maydaily close
304050607080JunJulAugSep65%65%65%Sep 16–17: +3 pts
Every sourceopen one for its contract
Prices by source
SourcePriceIn our figure?
RTWH model model68.9%No · forecast model
64.5%Yes · constructed
64.5%Yes
PM US63.7%No · editor-observed Sep 22
Gemini60.0%No · editor-observed Sep 22
64.5%Average of the two “Yes” rows
Disagreements

Where the sources don’t match, and why

Venue gap

Kalshi and Polymarket agree on a Democratic Senate

Compares
Polymarket’s Senate-control contract with Kalshi’s two-contract bundle
Same settlement?
Close, not identical. Kalshi’s contracts resolve on control in Feb 2027
Quotes observed
Polymarket 2 min old; Kalshi legs 6 and 18 min old
Tradable?
Yes. Buy Dem on Polymarket at 65¢

The gap has held for several days, which usually points to different traders rather than stale data.

Like-for-like

A Republican sweep costs 8.1¢ on Kalshi and 6.5¢ on Polymarket

Compares
Matching R House + R Senate contracts
Same settlement?
Yes, same question. Resolution dates differ slightly
Quotes observed
Kalshi 5 min; Polymarket 2 min
Tradable?
Yes, at the ask: Kalshi 8.1¢, Polymarket 7¢

Long shots are often priced higher on one venue. The 2-cent gap is about 20% of the price.

Our calculation vs. market

The 35 state races imply 69%. The control markets say 65%.

Compares
DeFi Rate’s combination of 35 Kalshi state prices with the Senate-control average
Same settlement?
Not applicable. One side is a calculation, not a contract
Assumes
Races are independent, which they aren’t
Tradable?
No. This is a consistency check, not a price

Races tend to move together, so the gap may be smaller than it looks. Treat it as a question to investigate, not a trade.

Forecast model vs. market

The Race to the WH forecast model gives Democrats 68.9%

Compares
A statistical forecast with the market average
Same settlement?
Not applicable. Models don’t settle
Observed
Model published Sep 22
Tradable?
No

Models and markets use different inputs. A model above the market means it’s more bullish on Democrats than traders are.

Scenario tool

Build your own Senate

Pick winners; we count the seats
MinnesotaKalshi favorite: Dem (87%)
New HampshirePappas (D) · Kalshi favorite: Dem (86%)
AlaskaPeltola (D) vs. Sullivan (R) · Kalshi favorite: Dem (73%)
MichiganEl-Sayed (D) vs. Rogers (R) · Kalshi favorite: Dem (72%)
TexasTalarico (D) vs. Paxton (R) · Kalshi favorite: Dem (64%)
OhioBrown (D) vs. Husted (R) · Kalshi favorite: Dem (63%)
MaineJackson (D) vs. Collins (R) · Kalshi favorite: Dem (59%)
IowaTurek (D) vs. Hinson (R) · Kalshi favorite: GOP (57%)
KansasKalshi favorite: GOP (65%)
South CarolinaKalshi favorite: GOP (87%)
FloridaKalshi favorite: GOP (88%)
MississippiKalshi favorite: GOP (90%)
NebraskaOsborn (I) vs. Ricketts (R) · Kalshi prices only “a Democrat wins” (<1%); it can’t tell us whether the independent or the Republican is ahead
Trading detail

Compare prices

Each venue’s price for the market you pick, what your order would pay, and the estimated fee.

Senate control: Democrats, all venues
Pick a market and an amount
Prices by venue
VenuePrice24h tradedEst. feePayout if correctTrade
KalshiStale quote: not observed recently, so it isn’t offered as a price to buy. Its last price and age are in the source record.
PolymarketSenate-control contract · quote 2 min old65¢Price to buy$53Kn/a$153before feesPolymarket65¢
Polymarket US63.7¢ observed on polymarket.us by an editor on Sep 22; not averaged.
Gemini60¢ observed on Gemini by an editor on Sep 22; not averaged.
OGSenate control isn't in our feed yet.

Kalshi has no single Senate-control contract; its price combines two contracts that settle in Feb 2027, so it isn’t marked as comparable with Polymarket.

“Price to buy” is the venue’s current ask; “last trade” is the most recent trade and may not be available now. We don’t yet measure how many contracts are available at a price, so large orders may fill higher. Est. fee uses Kalshi’s published taker-fee formula, per contract in a bundle; other venues’ fees aren’t in our feed. DeFi Rate may earn a commission when you open an account through these links. 18+ (21+ in some states).

Explanation

How midterm odds work, and how we measure them

How midterm prediction markets work

Each market asks a yes-or-no question, such as “Will Democrats control the Senate?” A contract pays $1 if the answer is yes and $0 if it’s no, so its price works as a probability: 64¢ means traders collectively put the chance at about 64%.

Take the Texas Senate race. If James Talarico trades at 58¢, 100 contracts cost $58. If he wins, they pay $100, a $42 profit before fees. If he loses, they’re worth nothing. You don’t have to hold until Election Day: if the price rises to 75¢ and someone is buying, you can sell early and keep the difference.

A price isn’t a poll. A candidate at 60¢ doesn’t have 60% of the vote; traders think they have about a 60% chance of winning.

What you can trade

  • Chamber control: which party wins the House and the Senate.
  • Balance of power: the four House/Senate combinations, such as a Democratic House with a Republican Senate.
  • Individual races: the winner of a given Senate, House or governor race.
  • Seat counts and margins: how many seats a party ends up with, or the national House popular-vote margin.

Kalshi, Polymarket US and Gemini are federally regulated US exchanges that offer these markets. Polymarket’s international exchange lists many of the same questions, but it isn’t available to US residents.

Why the venues show different prices

Nothing requires two exchanges to agree. Each has its own traders and order book, and some questions are built differently. Kalshi, for example, has no single Senate-control contract; its figure comes from adding two balance-of-power contracts. The source comparison shows every venue’s price next to ours, and labels which comparisons are like-for-like.

A gap isn’t free money. The displayed prices may not be available in size, fees reduce the difference, and the contracts may settle on slightly different terms.

Read the settlement rules

The market title isn’t the contract. Each one names its resolution source and says what happens after a recount, a runoff, a tie or a delayed certification. A network projection doesn’t settle anything. Every source record on this page links to the contract so you can read its rules before you trade.

How to place a trade

  1. Find the race in the race explorer and open its source record to see the exact contract.
  2. Compare the venues in Compare prices. It shows the quote to buy, recent activity and an estimated fee for your order size.
  3. Open the contract on the exchange, check its rules, and enter your amount. The exchange shows the final cost and payout before you confirm.
  4. Hold to settlement or sell earlier at the market price, if there’s a buyer.

In a thin market, the quoted price may only be available for a few contracts. Larger orders can fill at worse prices.

Kalshi, Gemini Titan and QCX LLC (which operates Polymarket US) are designated contract markets registered with the CFTC. The CFTC disapproved Kalshi’s congressional-control contracts in 2023; a federal court vacated that decision in 2024, and the appeal was dismissed in 2025. The CFTC chair has since warned that attempts to move political markets artificially could bring manipulation cases, and the Senate has barred senators and staff from trading these markets. Availability can still vary by platform and state, so check before you fund an account.

Explore midterm markets

Methodology

The two headline figures average Kalshi and Polymarket bid/ask midpoints for the same outcome. Kalshi has no single Senate-control contract, so its Senate price is built from its own two balance-of-power contracts and labeled “constructed.” State races use Kalshi alone. Open any Sources link for the exact contracts. Full methodology →

Full methodology
PricesEach venue is priced at the midpoint of its bid and ask where our feed has both, otherwise at its last trade, and every source record says which.
AveragesHeadline figures average the venues that list the same outcome. A venue without a single matching contract is labeled “constructed” or left out.
Timestamps“Data observed” is when prices were read; “Updated” is when an editor last changed the text.
Stale quotesQuotes our data provider marks stale are shown but never averaged.
Activity, not depth24-hour dollars traded is recent activity, not how much you can buy at a price.

Data and sources

Questions

Are the midterm odds on this page an average?
The two headline numbers are. Each is the equal-weight average of Kalshi and Polymarket, and every venue’s own price is shown in the source record and in Compare prices. State races use Kalshi’s contracts alone.
How often do these odds update?
Prices are checked every 2 minutes. Each page shows when the data was observed, separately from when the text was last edited. Quotes our data provider marks stale are still shown, with their age, but never offered as a price to buy.
Who is favored to win the Senate?
Democrats, at 65% as of Oct 4, 2026. The 51st Democratic seat is Ohio, where Sherrod Brown is at 63%.
Who is favored to win the House?
Democrats, at 93%.
What happens if a race goes to a recount or runoff?
It depends on the contract. Each one names its resolution source and says how runoffs, recounts and ties are handled. Open the source record for the contract link.
Can I use these numbers in a story?
Yes. Every figure has a citation and a permanent snapshot link that won’t change after the live page updates. Credit DeFi Rate and link to the snapshot.

About the authors

Pat Evans has covered complex industries for nearly two decades, including sports betting, sports business and, at iGaming Business, prediction markets, before joining DeFi Rate in 2026.

Cheryle Shepstone is DeFi Rate’s Director of Content and Strategy and oversees its prediction-market research, platform reviews and editorial methodology.

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