The NYPD’s budget this year is pegged at at $4.6 billion.

But taxpayers will have to shell out $8.3 billion to fully fund New York’s Finest through the fiscal year that ends on June 30.

The $3.7 billion difference represents pensions, fringe benefits, lawsuits and other costs that don’t get much attention in budget documents.

Mayor Bloomberg’s Office of Management and Budget has compiled a list of both the up-front and back-end costs of major city agencies and, helpfully, recently posted it in its section of the city’s website, http://www.nyc.gov.

“The mayor and his budget office deserve credit for this,”

said Doug Turetsk of the Independent Budget Office. “People can see what the full freight of city agencies really is.”

The posting also underscores the high cost of benefits, particuarly at the uniformed agencies, that Bloomberg has asked Albany for permission to reduce.

When it comes to benefits it would be hard to beat the Fire Department.

It has a budget of 1.7 billion. But the all-in cost is nearly double, $3.3 billion.