A Parliament period is the time period of a single Parliament between the date of its first assembly after a general election and the dissolution of that Parliament. Parliament periods are the same in both Houses. Parliaments of the United Kingdom are numbered ordinally from the first Parliament, sitting in 1801. A general election is held 25 days after a dissolution, excluding weekends or bank holidays.
| Parliament period | Summoned on | Dissolved on |
| 58 | 17 December 2019 | - |
| 57 | 13 June 2017 | 5 November 2019 |
| 56 | 18 May 2015 | 3 May 2017 |
| 55 | 18 May 2010 | 30 March 2015 |
| 54 | 11 May 2005 | 12 April 2010 |
| 53 | 13 June 2001 | 11 April 2005 |
| 52 | 7 May 1997 | 14 May 2001 |
| 51 | 27 April 1992 | 8 April 1997 |
| 50 | 17 June 1987 | 16 March 1992 |
| 49 | 15 June 1983 | 18 May 1987 |
| 48 | 9 May 1979 | 13 May 1983 |
| 47 | 22 October 1974 | 7 April 1979 |
| 46 | 6 March 1974 | 20 September 1974 |
| 45 | 29 June 1970 | 8 February 1974 |
| 44 | 18 April 1966 | 29 May 1970 |
| 43 | 27 October 1964 | 10 March 1966 |
| 42 | 20 October 1959 | 25 September 1964 |
| 41 | 7 June 1955 | 18 September 1959 |
| 40 | 31 October 1951 | 6 May 1955 |
| 39 | 1 March 1950 | 5 October 1951 |
| 38 | 1 August 1945 | 3 February 1950 |
| 37 | 26 November 1935 | 15 June 1945 |
| 36 | 3 November 1931 | 25 October 1935 |
| 35 | 25 June 1929 | 7 October 1931 |
| 34 | 2 December 1924 | 10 May 1929 |
| 33 | 8 January 1924 | 9 October 1924 |
| 32 | 20 November 1922 | 16 November 1923 |
| 31 | 4 February 1919 | 26 October 1922 |
| 30 | 31 January 1911 | 25 November 1918 |
| 29 | 15 February 1910 | 28 November 1910 |
| 28 | 13 February 1906 | 10 January 1910 |
| 27 | 3 December 1900 | 8 January 1906 |
| 26 | 12 August 1895 | 17 September 1900 |
| 25 | 4 August 1892 | 8 July 1895 |
| 24 | 5 August 1886 | 28 June 1892 |
| 23 | 12 January 1886 | 26 June 1886 |
| 22 | 29 April 1880 | 18 November 1885 |
| 21 | 5 March 1874 | 24 March 1880 |
| 20 | 10 December 1868 | 26 January 1874 |
| 19 | 1 February 1866 | 11 November 1868 |
| 18 | 31 May 1859 | 6 July 1865 |
| 17 | 30 April 1857 | 23 April 1859 |
| 16 | 4 November 1852 | 21 March 1857 |
| 15 | 18 November 1847 | 1 July 1852 |
| 14 | 19 August 1841 | 23 July 1847 |
| 13 | 15 November 1837 | 23 June 1841 |
| 12 | 19 February 1835 | 17 July 1837 |
| 11 | 29 January 1833 | 29 December 1834 |
| 10 | 14 June 1831 | 3 December 1832 |
| 9 | 26 October 1830 | 23 April 1831 |
| 8 | 14 November 1826 | 24 July 1830 |
| 7 | 21 April 1820 | 2 June 1826 |
| 6 | 14 January 1819 | 29 February 1820 |
| 5 | 24 November 1812 | 10 June 1818 |
| 4 | 22 June 1807 | 29 September 1812 |
| 3 | 15 December 1806 | 29 April 1807 |
| 2 | 16 November 1802 | 24 October 1806 |
| 1 | 22 January 1801 | 29 June 1802 |