[a] Voting for the Parliament is on the basis of universal suffrage, which comprises all nationals over 18 years of age, registered in Catalonia and in full enjoyment of their political rights.

The 135 members of the Parliament of Catalonia are elected using the D'Hondt method and a closed list proportional representation, with a threshold of three percent of valid votes—which includes blank ballots—being applied in each constituency.

Seats are allocated to constituencies, corresponding to the provinces of Barcelona, Girona, Lleida and Tarragona, with each being allocated a fixed number of seats:[1][2] In smaller constituencies, the use of the electoral method results in an effective threshold based on the district magnitude and the distribution of votes among candidacies.

[1] The president has the prerogative to dissolve the Parliament of Catalonia and call a snap election, provided that no motion of no confidence is in process and that dissolution does not occur before one year has elapsed since a previous one under this procedure.

The highest percentage figure in each polling survey is displayed with its background shaded in the leading party's colour.