House GOP Speaker nominee Mike Johnson (R-La.) heads to the House floor at noon Wednesday for a House-wide floor election.

While momentum is in his favor, he is not yet assured to win on the House floor. 

Here is how the process works and what he needs to win.

Johnson needs a majority of all members present and voting for a specific candidate in order to win the GOP nomination. 

There are two vacancies in the House right now, due to resignations of one Republican (Chris Stewart of Utah) and one Democrat (David Cicilline of Rhode Island), making a total of 433 members. House Republicans have 221 members, while Democrats have 212.

That means a majority of the House right now is 217 members — the number often referenced as what Johnson needs to win the Speakership.

All voting Democrats are expected to vote for House Minority Leader Hakeem Jeffries (D-N.Y.) for Speaker.

So, if more than four of the 221 Republicans defect from Johnson, he is below 217 and in hot water.

However, 217 is not the end-all-be-all magic number to win the Speakership. Members who are absent or vote “present” lower the threshold needed to win, since the winner is decided by all members voting for a specific candidate.

That is how ousted Speaker Kevin McCarthy (R-Calif.) won the Speakership on his 15th ballot in January with 216 votes; six “present” votes from Republicans lowered the threshold needed to win, even though a majority of the whole House was 218.

Former Speaker Nancy Pelosi (D-Calif.) won the Speakership with 216 in 2021, too, as did former Speaker John Boehner (R-Ohio) in 2015.

Because of the slim margins, Democrats have urged full attendance for all members, since their absences can affect the margins that Republicans need, too.

To find the “magic number” needed to win the Speakership if there are present votes and absences, take 433 and subtract the number of present votes and absences. Divide that number by two — and then count up to the next whole number.

But Johnson does not necessarily want to count on absences and “present” votes to win.

And he seems to have the wind at his back. Republican lawmakers running the gamut from moderate Rep. Mike Lawler (R-N.Y.) to hard-line conservative Rep. Matt Gaetz (R-Fla.) say they support him.

He also got backing from two previous Speaker nominees — Majority Leader Steve Scalise (R-La.) and Judiciary Committee Chair Jim Jordan (R-Ohio) — as well as McCarthy.