Google said the data painted an incomplete picture of how its workers are paid, because it did not take into account different roles at the company, job performance and where the employees are based. Based on its own January 2017 analysis, Google said that, accounting for factors like tenure, job role and performance, female employees earned 99.7 cents to every dollar earned by men.

In the suit, Kelly Ellis, a former Google software engineer and one of the three plaintiffs, says that when the company hired her in 2010, she was brought in as a Level 3 employee — a term for entry-level software engineers who are new college graduates — despite having four years of work experience.

Within a few weeks of her hiring, the suit says, Google hired a male engineer onto her team who, like Ms. Ellis, had graduated from college four years earlier. But, the suit says, he was hired as a Level 4 employee, meaning he was paid a higher salary and had more opportunities for bonuses, raises and stock compensation. The suit says that other men on Ms. Ellis’s team whose qualifications were equal to or less than hers were also brought in at Level 4.

Google also segregated by roles within its engineering ranks, the suit says. Ms. Ellis had experience as a back-end engineer — a job that involves managing large systems like servers and databases — but was assigned to a front-end engineering role dealing with parts of a service that users interact with.

At Google, the suit says, back-end engineering jobs are considered more technically rigorous and more prestigious and that Google pays back-end engineers more and promotes them faster. Ms. Ellis, who left the company in 2014, says that almost all of the female software engineers at Google worked in front-end jobs while men worked in back-end roles. (After she left the company, Ms. Ellis accused a former manager of sexual harassment.)

A second plaintiff, Holly Pease, who worked at Google for 11 years and left in 2016, says in the suit that she was denied opportunities to gain status as a “technical” employee. Such employees earn more than nontechnical employees. She did not gain that status, despite having more than 10 years of experience as a network engineer and managing a Google team made up mostly of technical staff members.

The suit cites the Labor Department’s review of compensation data for all 21,000 employees at Google’s Mountain View, Calif., headquarters for 2015, which found that the pay disparity between men and women was significant enough that there was “a one in 100 million chance” that it was occurring by chance.