Passengers are incurring hidden charges with Uber’s “upfront” pricing model — resulting in a $7.4 million windfall per month to the app-ride company from New York City trips alone, according to a new class-action lawsuit.

Uber launched its upfront fares last summer, promising a “no math and no surprises” system that would calculate the actual cost of a trip before customers booked a ride.

But Uber is charging riders approximately $2 more than the actual cost of the trip, according to the Brooklyn lawsuit filed by Coney Island resident Jacqueline Gayed.

For example, while the rider pays $14 for a trip, the driver’s Uber platform shows a fare of just $12.

“Uber simply pockets the difference,” the suit says.

The company pulls off the scheme by showing riders a less efficient route than the one drivers take, according to court papers.

The suit cites a recent investigation by the website The Rideshare Guy, which found that Uber is hitting half of riders taking the daily 250,000 trips in New York City with the extra $2 charge. So Uber is making about $250,000 a day or $7.4 million a month “in New York City alone” from the hidden fee, the suit says.

Gayed assumes Uber is taking in similar windfalls in other cities.

The suit was filed the day after Uber admitted it owes drivers tens of millions of dollars in back pay for taking its fee before deducting taxes and other surcharges.

California drivers filed a similar class-action lawsuit over the upfront pricing model in April.

A spokeswoman for Uber was looking into the claims.