The term of Australian parliaments is determined by the opening and dissolution (or expiration) of the House of Representatives.
The maximum term permitted by section 28 of the Constitution of Australia is three years, counted from the date the parliament first meets after a general election.
However, the Governor-General, acting on the advice of the Prime Minister, may dissolve the parliament earlier.
The average length of completed parliaments since Federation has been about 2 years, 130 days.
This has happened on a number of occasions, most recently between the 2019 and 2022 elections (3 years 3 days).