The Senate has 100 members, elected for six year terms in dual-seat constituencies, two from each state. One-third are renewed every two years. The group of the Senate seats that is up for election during a given year is known as a class.
The House of Representatives has 435 members, elected for two year terms in single-seat constituencies. House of Representatives elections are held every two years on the first Tuesday after November 1 in even years, correlated with presidential elections..
