Every city worker will earn at least $15 an hour by the end of 2018 under pay raises Mayor Bill de Blasio is set to announce Wednesday that will cover 50,000 people and cost $200 million over the next four years or so, according to the mayor’s office.

Some of the affected workers are now paid as little as $11.50 an hour — meaning they would gain a raise of more than 30 percent.

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De Blasio’s announcement is to be held at the union offices of DC 37 in lower Manhattan, some of whose workers, such as school crossing guards, park aides and seasonal workers, will be covered by the increase.

Also affected are workers for the union 32BJ, which represents building services workers.

De Blasio has said he wants to raise New York City’s minimum wage for everyone to $15 an hour, but can’t do it without the green light from the state. Last year, his effort to enact a $13 minimum wage in the city was turned down in Albany.

Earlier this week, Gov. Andrew M. Cuomo said he was gradually increasing the minimum hourly wage to $15 for tens of thousands of state university workers. He said he wants the legislature to grant a similar wage to all workers.

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On Thursday, de Blasio is set to sign an executive order granting six weeks of parental leave to nonunion employees, a move that will cover about 20,000, said de Blasio spokeswoman Amy Spitalnick. It’s retroactive to Jan. 1.