The table below shows registered voter turnout for all UK Parliamentary by-elections since the 1997 general election, with the most recent first.
To view the results of each by-election click on the constituency names.
| Copeland — Con gain |  51.33% |
| Stoke–on–Trent Central — Lab hold |  38.16% |
| Sleaford and North Hykeham — Con hold | 37.1% |
| Richmond Park — Lib Dem gain |  53.6% |
| Witney — Con hold | 46.74% |
| Batley and Spen — Lab hold | 25.8% |
| Tooting — Lab hold | 42.5% |
| Ogmore — Lab hold | 43% |
| Sheffield Brightside & Hillsborough — Lab hold | 33.2% |
| Oldham West & Royton — Lab hold | 40.26% |
| Rochester & Strood — UKIP gain |  50.67% |
| Clacton — UKIP gain | 51% |
| Heywood & Middleton — Lab hold | 36% |
| Newark — Con hold | 52.79% |
| Wythenshawe & Sale East — Lab hold | 28.2% |
| South Shields — Lab hold | 39.2% |
| Mid Ulster — Sinn Féin hold |  55.7% |
| Eastleigh — Lib Dem hold | 52.8% |
| Croydon North — Lab hold | 26.4% |
| Middlesbrough — Lab hold | 25.9% |
| Rotherham — Lab hold | 33.6% |
| Corby — Lab gain | 44.8% |
| Cardiff South & Penarth — Lab hold | 25.65% |
| Manchester Central — Lab hold | 18.16% |
| Bradford West — Respect gain |  50.78% |
| Feltham & Heston — Lab hold | 28.8% |
| Inverclyde — Lab hold | 45.5% |
| Belfast West — Sinn Féin hold | 37.5% |
| Leicester South — Lab hold | 34.2% |
| Barnsley Central — Lab hold | 36.5% |
| Oldham East & Saddleworth — Lab hold | 48% |
| Glasgow North East — Lab hold | 33.02% |
| Norwich North — Con gain | 45.88% |
| Glenrothes — Lab hold | 52.37% |
| Glasgow East — SNP gain |  42.25% |
| Haltemprice & Howden — Con hold | 34.03% |
| Henley — Con hold | 50.32% |
| Crewe & Nantwich — Con gain | 58.2% |
| Ealing Southall — Lab hold | 42.9% |
| Sedgefield — Lab hold | 41.5% |
| Blaenau Gwent — Ind hold |  51.7% |
| Bromley & Chislehurst — Con hold | 40.5% |
| Dunfermline & West Fife — Lib Dem gain | 48.7% |
| Livingston — Lab hold | 38.6% |
| Cheadle — Lib Dem hold | 55.2% |
| Hartlepool — Lab hold | 45.8% |
| Birmingham Hodge Hill — Lab hold | 37.9% |
| Leicester South — Lib Dem gain | 40.6% |
| Brent East — Lib Dem gain | 36.2% |
| Ogmore — Lab hold | 35.2% |
| Ipswich — Lab hold | 40.2% |
| Falkirk West — Lab hold | 36.2% |
| West Bromich West — Lab hold | 27.6% |
| Glascow Anniesland — Lab hold | 38.4% |
| Preston — Lab hold | 29.6% |
| South Antrim — DUP gain |  43% |
| Tottenham — Lab hold | 25.4% |
| Romsey — Lib Dem gain | 55.5% |
| Ceredigion — PC hold |  45.6% |
| Kensington & Chelsea — Con hold | 29.7% |
| Wigan — Lab hold | 25% |
| Hamilton South — Lab hold | 41.3% |
| Eddisbury — Con hold | 51.4% |
| Leeds Central — Lab hold | 19.6% |
| Winchester — Lib Dem hold | 68.7% |
| Beckenham — Con hold | 43.6% |
| Paisley South — Lab hold | 43.1% |
| Uxbridge — Con hold | 55.5% |
Source: House of Commons Research papers 01/37, 05/34, 08/12; Press Association