House Majority Prediction & Seat Calculator Live 2026

Evaluating Kalshi Market Odds & Congressional Seat Probability Curves
Benchmarked: @Kalshi 86% Dem Majority via Spectator Index
Democratic Win Odds MAJORITY >= 218
86.4%
Projected Seats: 226
Republican Win Odds MAJORITY >= 218
13.6%
Projected Seats: 209
Tipping Point Margin DISTRICT #218
+1.4% Dem
Critical seat deciding majority control
Competitive Toss-Ups WITHIN ±3.5%
22
Dem: 14 • GOP: 8 under model
Probability Density of Democratic Seats Won (Total: 435)
GOP Majority (<218)
Dem Majority (≥218)
Threshold (218)
Forecasting Scenarios & Presets
Uniform National Popular Swing +2.5% Dem
+6.0% GOP Wave Neutral (0.0%) +6.0% Dem Wave
Toss-Up Democratic Win Rate 63% Dem
15% (Heavy GOP split) 50% (Pure coin-flip) 85% (Clean Dem sweep)
Forecast Variance / Uncertainty (σ) ±7.5 Seats
Low volatility (±4) Medium (±7.5) High uncertainty (±14)
Key Toss-Up District Ledger (Sample Battlegrounds) Adjusted for Current Swing
District Incumbent Base Margin Sim. Margin Model Favored
* Tipping point district is highlighted in gold. Margin accounts for uniform swing + localized toss-up factor.
Export complete simulation state, seat probability curve points, and district allocations:
Methodology & Market Calibration: Prediction odds grounded in Kalshi contract "Which party wins the House of Representatives?" pricing (calibrated at 86% Democratic probability per The Spectator Index dispatch, Sept 2026). Distribution modeling applies a discretized Gaussian cumulative density function over 435 voting districts, integrating standard deviation uncertainty bounds with baseline Cook/Sabato style seat ratings (204 Solid/Likely Dem, 187 Solid/Likely GOP, 22 Toss-ups, 22 Lean seats).
Enjoy this tool? Build your own with Super