Enter your own polling percentages for each party (Labour, Conservative, Reform UK, Liberal Democrats, Greens, SNP, Plaid Cymru, Others). The calculator will automatically project Westminster seats using uniform national swing methodology and display results with seat counts, vote shares, and detailed constituency breakdowns.

Uniform national swing applies the same vote share change to every constituency. If Labour gains 5% nationally, we add 5% to Labour's vote share in every seat, then determine the winner. This is a simplified model that doesn't account for local factors.

Yes, the Custom Seat Calculator includes tactical voting scenarios. You can select options like Anti-Reform Coalition, Progressive Alliance, or Conservative-Reform Alliance to see how tactical voting might affect seat outcomes in marginal constituencies.

Projections are estimates based on uniform national swing. Accuracy depends on how realistic your input polling numbers are and how close to an election you're projecting. Local factors, candidate quality, and regional variations aren't captured by UNS, so treat projections as estimates.

The calculator displays projected seat counts for each party, vote share percentages, seat swings from GE2024, and a detailed breakdown of constituency results. You can also view marginal seats, filter by region, and see how tactical voting scenarios would affect outcomes.