The UKIP performance in each of the 40 by-elections the party has contested since the General Election, 80% of the total of 50 upto and including 3rd September, can be summarised by:
| Date of Election | Authority | Ward / Division | By-election share | Change in share - average basis | Last contested |
| 4th June | Cambridgeshire | Wisbech South | 18.6% | -19.6% | 2013 |
| 11th June | Sutton | Wallington South | 5.8% | -11.8% | 2014 |
| 11th June | Tower Hamlets | Stepney Green | 5.2% | -3.6% | 2014 |
| 25th June | Cambridgeshire | Romsey | 2.1% | from nowhere | |
| 2nd July | Lincolnshire | Grantham Barrowby | 15.3% | from nowhere | |
| 2nd July | Richmond upon Thames | Hampton Wick | 2.5% | from nowhere | |
| 9th July | East Sussex | Old Hastings & Tressall | 10.2% | -12.2% | 2013 |
| 9th July | Hastings | Central St Leonards | 7.0% | -8.8% | 2014 |
| 9th July | Hastings | St Helens | 7.9% | -13.9% | 2014 |
| 9th July | Hounslow | Brentford | 4.7% | -8.2% | 2014 |
| 9th July | Hyndburn | Spring Hill | 9.7% | -6.1% | 2014 |
| 9th July | North Lanarkshire | Thorniwell | 0.9% | from nowhere | |
| 9th July | Sandwell | Newton | 15.9% | -7.3% | 2015 |
| 16th July | Kingston upon Thames | Grove | 2.2% | -2.5% | 2015 |
| 16th July | Norfolk | Gorleston St Andrews | 13.9% | -22.8% | 2013 |
| 16th July | Norfolk | Mile Cross | 10.2% | -11.4% | 2015 |
| 16th July | Rother | Battle Town | 8.2% | from nowhere | |
| 16th July | Tendring | Rush Green | 38.5% | -10.0% | 2015 |
| 16th July | Wrexham | Llay | 4.5% | from nowhere | |
| 23rd July | Blackburn with Darwen | Mill Hill | 20.8% | -7.5% | 2015 |
| 23rd July | Caerphilly | New Tredegar | 11.5% | from nowhere | |
| 23rd July | Elmbridge | Long Ditton | 4.0% | -4.8% | 2015 |
| 23rd July | North East Lincolnshire | Croft Baker | 15.3% | -8.0% | 2015 |
| 23rd July | Westminster | Harrow Road | 2.5% | -7.4% | 2014 |
| 30th July | Northumberland | College | 14.0% | from nowhere | |
| 30th July | Wychavon | Droitwich East | 18.0% | -3.1% | 2015 |
| 6th August | Glasgow | Anderston / City | 1.4% | from nowhere | |
| 6th August | Glasgow | Calton | 3.8% | from nowhere | |
| 6th August | Glasgow | Craigton | 1.9% | +1.0% | 2012 |
| 6th August | Glasgow | Langside | 1.5% | from nowhere | |
| 6th August | South Lanarkshire | Hamilton South | 1.1% | -1.4% | 2013 |
| 13th August | Caerphilly | Cross Keys | from nowhere | ||
| 13th August | Exeter | Pinhoe | 2014 | ||
| 13th August | North Lanarkshire | Wishaw | from nowhere | ||
| 13th August | Warwickshire | Nuneaton Whitestone | from nowhere | ||
| 20th August | Cornwall | Camborne Pendarves | 2013 | ||
| 20th August | Durham | Shotton & South Hetton | from nowhere | ||
| 20th August | West Oxfordshire | Witney North | 2015 | ||
| 27th August | Barnsley | Dearne North | 2015 | ||
| 3rd September | Caerphilly | Bedwas, Trethomas & Machen | from nowhere |