It looks like the NYPD will exceed its overtime budget by nearly 20% this fiscal year, spending $111 million more than the expected $615 million. But the big worry is: Why?

The fiscal year runs through June, and its first six months brought no major terror attack, crime outbreak or other incident that could explain the overage, reported this week by the state Financial Control Board.

One inside source told The Post that the brass are to blame: “It takes labor and pain to actively manage overtime, and that’s not happening right now.”

Perhaps the department’s leaders have just been too busy keeping crime down even as the City Council and state lawmakers make it ever harder for cops to do their jobs.

The brass may also be worried about morale in the wake of new waves of public disrespect of police officers — as well as resentment of the treatment of former Officer Daniel Pantaleo, fired over the 2014 death of Eric Garner after he resisted arrest.

Count it as one more problem for new Commissioner Dermot Shea.

With the state’s “no bail” law now putting all but the most violent accused criminals back on the streets soon after their arrests, and also forcing prosecutors to jump through new hoops, we fear that NYPD overtime won’t shrink — but soar.