Work out margin of victory instantly with clear inputs, formula shown and shareable results.
Margin of victory as a percentage of valid votes is the standard measure of how safe a seat is, and it determines how much swing is needed to flip it. The winner's share of the total electorate is a separate and often sobering figure, since it accounts for non-voters.
Margin
Margin = Winner's votes - Runner-up's votes
Margin percentage
Margin % = Margin / Total valid votes x 100
Indicative estimate only. Fees, entitlements, limits and formulas vary by jurisdiction, statute, policy wording and the facts of the case. This is not legal, tax, insurance or financial advice — confirm with a qualified professional or the relevant authority.
Roughly half the margin percentage, since a swing moves votes from one party to the other and counts in both directions.
Conventionally a margin under 5% of valid votes, though analysts use anything from 3% to 10% depending on the system.