At that point, the company may have results from its latest trial on whether the vaccine candidate would prove to be safe and effective enough to send for approval to the Food and Drug Administration (FDA) for consumer use, CEO Albert Bourla told NBC's "Today" show.
This does not mean the shots will be approved for use, he said.
"When the study will read out depends on multiple variables. But right now ... our best case predicts that we will have an answer by the end of October," Bourla said.
While only a prediction based on one of the company's models, according to Bourla, he said there is a 60% chance that Pfizer will have an answer to the safety and effectiveness based on its predicted timeline.
For Pfizer's vaccine, Bourla said its phase three trial is "progressing very well" with 25,000 patients already recruited.
The news comes just after the company joined eight other leading coronavirus vaccine developers in vowing to prioritize safety before speed by waiting to seek emergency government approval until trials have evidence to support safe treatment.
"In this pledge, all the companies are saying that we will only submit for authorization when we have evidence of safety and efficacy," Bourla said.
Pfizer, along with AstraZeneca, BioNTech, GlaxoSmithKline, Johnson & Johnson, Merck, Moderna, Novavax and Sanofi, released the joint statement on Tuesday regarding their "on-going commitment to developing and testing potential vaccines for COVID-19 in accordance with high ethical standards and sound scientific principles."
The CEOs of each company promised not to apply for FDA approval, even for emergency use, until certain standards are met.
"We believe this pledge will help ensure public confidence in the rigorous scientific and regulatory process by which COVID-19 vaccines are evaluated and may ultimately be approved," according to the joint statement.
This will work to "ensure a sufficient supply and range of vaccine options, including those suitable for global access," the statement read.
The statement comes amid concerns that a COVID-19 vaccine is being rushed to market before the November presidential election.
President Trump previously noted the U.S. remains on track to deliver a vaccine before the end of the year and "maybe even before Nov. 1."
Representatives for Pfizer have not immediately responded to FOX Business' request for comment.
FOX News' Danielle Wallace contributed to this report.