Since changes introduced in May 2005, the Commons sits on Mondays and Tuesdays from 1430 to 2230.
On Wednesdays the House sits from 1130 to 1930, on Thursdays from 1030 until 1830 and on Fridays from 0930 to 1500.
During the parliamentary year there are a number of Fridays on which the House does not sit, allowing MPs to attend to constituency business.
The government tries to deal with its most important business early in the week to allow MPs to spend plenty of time in their constituencies over the weekend.
But it came under fire from some MPs for the decision to make rising times more predictable by strictly timetabling debates.
The reforms removed the ability of backbench and opposition MPs to force concessions from the government by filibustering - but made it easier for the government to push through its legislative programme.
On rare occasions, Parliament will sit at weekends to debate important business like the start of the Falklands conflict on Saturday 3 April 1982.
The only Sunday sitting since 1900 occurred at 12 noon on 3 September 1939, following the declaration of war with Nazi Germany.
A spill-over chamber for Commons debates was established when Labour came to power in 1997.
The debates in Westminster Hall allow backbenchers to air topics of concern.
They take place on Tuesdays and Wednesdays from 0930 until 1130 then 1400 until 1630 and on Thursdays from 1430 for a maximum of three hours.
House of Lords
The House of Lords normally sits on Mondays and Tuesdays from 1430, on Wednesdays from 1500, and on Thursdays from 1100.
As the timetable of debates is self-regulated, the upper chamber rises when business is concluded and not at a fixed time.
The House of Lords tends not to sit on a Friday, but on the occasions that it does, business starts at 1000.