The representation formula
Below is the formula for allocating seats in the House of Commons following each decennial (10-year) census. This Representation Formula is found in subsection 51(1) of the Constitution Act, 1867.
Provincial population ÷ electoral quotient = initial provincial seat allocation
Applying the Senatorial Clause and Grandfather Clause
Applying the Representation Rule
Total provincial seats + One seat per territory = Total number of seats
1 – Initial Allocation of Seats to the Provinces
The total population of each province is from Statistics Canada's quarterly population estimate of July 1, 2021. The electoral quotient is obtained by multiplying the quotient of the last decennial redistribution (111,166) by the average of the population growth rates of the 10 provinces (9.647%) in the last 10 years. The new electoral quotient thus calculated is 121,891. The number of seats initially allocated to each province is calculated by dividing the population number of each province by the electoral quotient. This figure is then rounded up to the next whole number.
2 – Applying the Special Clauses
After the initial number of seats per province is obtained, adjustments are made to account for the Senatorial Clause and the Grandfather Clause. The Senatorial Clause guarantees that no province has fewer seats in the House of Commons than it has in the Senate. The Grandfather Clause guarantees each province no fewer seats than it had in the 43rd Parliament elected in 2019.
3 – Applying the Representation Rule
The Representation Rule will only apply to a province whose population was overrepresented in the House of Commons at the completion of the last redistribution process. As per this rule, if such a province would now be under-represented based on the calculations above, it will be given extra seats so that its share of House of Commons seats is proportional to its share of the population.
Once the special clauses and Representation Rule are applied, the number of seats for each province has been determined.
4 – Calculating the Total Number of Seats in the House of Commons
Once the special clauses and Representation Rule are applied, the number of seats for each province has been determined. Three seats are then allocated to the territories–one each for Yukon, Northwest Territories, and Nunavut – to obtain the total number of seats in the House of Commons.