"How many seats in total are in Parliament House?"

There are 150 Members of the House of Representatives and 76 Senators.  These 226 positions are sometimes referred to as seats in parliament. To win a seat in the House of Representatives, you must be elected by the voters of your electorate. To win a seat in the Senate, you must be elected by the voters of your state or territory.

diagram to help explain How many seats in total are in Parliament House?