Subway ridership has nearly halved at Manhattan’s busiest stations, according to a new report.

Turnstile entries were 39 percent lower citywide last Friday compared to a week earlier, according to an analysis by The City of data from 4,375 turnstiles at 450 stations, accounting for the vast majority of the subway system.

Stations in the once-bustling Manhattan core saw the biggest drops: Ridership was down 48 percent at Grand Central, 43 percent at Penn Station, 40 percent at Port Authority and 39 percent at Herald Square.

“It’s been dead mostly,” one transit worker told The Post.

Ridership has been steadier in the outer boroughs.

In the Bronx, just 16 percent fewer people took the train on Friday compared to the previous week. Queens and Brooklyn saw drops of 22 percent and 28 percent, respectively, while Manhattan entries were down 40 percent.

The ridership drops largely track with proximity to Manhattan’s central business district, with notable exceptions being Bay Ridge, Brooklyn and Kew Gardens, Queens.

A drop in straphangers means a drop in revenue, which could leave the MTA without cash to operate — and transit workers tell The Post that the agency is aflutter with speculation about whether service will be reduced as a result of low ridership.

But buses and subways chief Sarah Feinberg insisted the agency has no plans to change service right now.

Virus Outbreak New York
A subway customer walks through an empty underground passage in Brooklyn.

AP

Virus Outbreak New York
A subway rider waits to board a car at York Street in Brooklyn.

John Minchillo/AP

“We have no plans to alter service at this time,” Feinberg said.

“We always have contingency plans ready for any circumstance, including Saturday service, Sunday service and other options,” she said. “We can go to any of them relatively quickly. That’s why we plan for all scenarios.”