The MTA is losing $125 million per week amid the coronavirus pandemic — and a $3.8 billion federal bailout won’t be enough to keep the struggling transit system above water alone, officials said Wednesday.

“We need $4 billion, but we’re only at the starting point of the crisis,” MTA Chairman Pat Foye said at a video-conference board meeting.

“We will need substantially more than that to survive. We’re the lifeblood of the New York economy. The state can’t recover without a strong public transportation system.”

According to Senate Minority Leader Chuck Schumer, the MTA stands to receive $3.8 billion from the Senate’s massive economic stimulus deal,

But the agency — which has seen subway ridership plummet almost 90% — stands to end the year with a $6.5 billion deficit, officials said.

MTA Chief Financial Officer Bob Foran said the system would still be running at a loss even if it were to recover to 100% ridership over the next six months — something the agency sees as unlikely.

“Our farebox and toll revenue is about $8.5 billion in a normal year, about half of the money needed to run the MTA,” Foye said. “That’s lost revenue we’ll never recover”

In the meantime, officials said they can scrape another $3 billion total from the MTA’s capital budget and additional borrowing. The agency has also suspended new capital construction spending indefinitely.

The agency’s sliver of the $25 billion federal bailout pie means smaller cities are getting disproportionately more relief, advocates griped.

“The $25 billion for public transit in the federal relief bill is an important start,” Betsy Plum of the NYC-based Riders Alliance said in a statement. “In whatever relief comes next, New Yorkers, who make up 38% of transit riders nationwide, deserve better than 15% of federal transit rescue dollars.”

Subway ridership is down 87 percent this week compared to the same time last year.

On Wednesday, the MTA began to scale back subway service. Buses and commuter rails will see similar service reductions later in the week.