The Liberals won all three by-elections held on 31 August 2026 with absolute majorities, despite only having held two of those three ridings beforehand; they therefore have gained one seat in the House of Commons. As of 1 September 2026, an additional five seats stand vacant, which will soon necessitate five more by-elections. While the House of Commons’ website lists five vacancies as of 1 September 2026, Elections Canada’s webpage on “Vacant Seats in the House of Commons Since the 2025 General Election” only lists four as of 1 September 2026, presumably because the Chief Electoral Officer has not yet received the Speaker’s warrant declaring that Conservative MP Cathey Wagantall has vacated the seat for Yorkton—Melville in Saskatchewan. Reports suggest that she did, however, formally resign, either on 31 August 2026 or 1 September 2026.[1] Larry Brock, the Conservative MP for Brantford—Brant South (which CBC News still deadnames as Brantford—Brant South—Six Nations, notwithstanding an Act to rename certain electoral districts, 2026) announced in August that he would also resign as an MP on 18 September 2026, three days for the House of Commons reconvenes in the fall.[2]

Under section 31(1) of the Parliament of Canada Act, a writ for a by-election “shall be issued  between the 11^th and 180^th day” after the Chief Electoral Officer receives the Speaker’s warrant certifying that a seat has become vacant; furthermore, under section 57(1.2)(c) of the Canada Elections Act, the writperiod for a general election or a by-election must last between 36 and 50 days.[3] Taken together, therefore, a by-election can be held at the earliest 47 days after the Chief Electoral Officer receives the Speaker’s warrant, which combines the minimum duration of the writperiod at 36 days with the 11 days after the Chief Electoral Officer obtains the Speaker’s Warrant. And this, in turn, would make the latest date to hold a by-election 230 days after the Chief Electoral Officer receives the Speaker’s warrant, and not the 180 days that Elections Canada lists, because we need to add together the 180 days after the Chief Electoral Officer receives the Speaker’s warrant and the maximum duration of the writ at 50 days.

However, polling day must happen on a Monday according to section 57(3) of the Canada Elections Act, which means either that we would need to account in our calculation either adding up to six days on the core calculation of 180 plus 36 (180 plus 36 and plus six) so that the voting day falls on the following Monday, or that we would need to set the voting day on the earlier Monday so that the writ does not exceed the maximum of 50 days (180 plus 50 and minus six).[4] Elections Canada did not acknowledge any of this in its calculations because it used a less pertinent category in its datatable.

• Upcoming By-Elections

All that work with the Loosemore-Hanby Index and reconstructing all iterations of the Representation Formula for my two upcoming academic monographs Where to Draw the Line: Readjusting Federal Electoral Boundaries in Canada and Representation by Population in the House of Commons of Canada has made me more enthusiastic toward spreadsheets, so I created another to track the next round of federal by-elections. The worksheet includes dates for when the Chief Electoral Officer received the Speaker’s warrant, the earliest dates on which the by-election could start and then be held under the Parliament of Canada Act and the Canada Elections Act, as well as the latest dates on which the by-elections could start and be held. Once the Governor-in-Council makes its decision, I would fill in the columns showing the dates fixed by Order-in-Council for issuing the writ the voting itself, as well as the number of days between those two dates – which would presumably use the two sets of earlier dates which I have predicted and calculated presuming the minimum writ of 36 days. In particular, I find my datapoint on “Latest Date to Hold the By-Election” more useful that Election Canada’s entry for the “latest date to announce by-election” in its incomplete datatable.

As of 1 September 2026, the House of Commons records the following ridings as vacant:

1. Saint-Hyacinthe—Bagot—Acton
2. Scarborough North
3. Rosemont—La Petite-Patrie
4. Laurier—Sainte-Marie
5. Yorkton—Melville

Elections Canada records that the Chief Electoral Officer obtained the Speaker’s warrant certifying the vacancy in Saint-Hyacinthe—Bagot—Acton on 22 June 2026, the same day that he received word that John Wilkinson had resigned from North Vancouver—Capilano, so I do not understand why the Carney government excluded the former from the round of by-elections already held on 31 August. But if Larry Brock resigns on Friday, 18 September as planned, then the Chief Electoral Officer might not obtain the Speaker’s warranty certifying that Brantford—Brant South has become vacant until the following Monday, 21 September 2026. This would, in turn, make Monday, 9 November 2026 the earliest date at which the voters of Brantford—Brant South could elect their new MP. Brock’s resignation would come last and make for a total of six, which would also make Monday, 9 November 2026 the best date on which to fill up all six of these vacant seats in the House of Commons. The Governor-in-Council would therefore have to set the beginning of the writperiod as of 4 October 2026 to make the minimum of 36 days, though the Carney government might make the announcement a bit earlier, such as on Friday, 2 October instead. This is what I would expect, but we’ll see what happens!

Notes

[1] Aishwarya Dudha, “Yorkton—Melville MP Cathay Wagantell to Step Down Aug. 31, Earlier Than Planned,” CBC News, 17 June 2026; David Baxter, “Yorkton—Melville MP Cathay Wagantall Officially Resigns Seat,” CBC News, 1 September 2026.

[2] CBC News, “Ontario Conservative MP Larry Brock to Exit Parliament in September,” 6 August 2026.

[3] Parliament of Canada Act, R.S.C., 1985, c. P-1, at section 31(1); Canada Elections Act, S.C. 2000, c. 9, at section 57(1.2)(c).

[4] Canada Elections Act, S.C. 2000, c. 9, at section 57(3).