The long-dreaded day is finally here. Millions of harried Americans have until 5 p.m. today to mail off their 1040 forms to the tax man. They have all been working feverishly in search of deductions and loopholes, hoping that the IRS will dock them for the least amount possible.

But for Harvard, the question is not how little to give but how much. In addition to the approximately $1.6 million it is required to pay to the city, the University throws in an additional $800,000 in voluntary payments to Cambridge.

Because the University is a nonprofit institution, it is exempted from paying property taxes on its academic holdings, though not its commercial holdings. But each year, Harvard makes a voluntary contribution to the City of Cambridge to pay for such vital services as fire department protection and education for schoolchildren.

"Cambridge has a very heavy presence of tax exempt universities," said Jacqueline O'Neill, associate vice president for state and community affairs. O'Neill said that Harvard and MIT, which are the only universities to follow a voluntary tax plan, serve as "a model for other communities."

MIT deposits $700,000 in city coffers in addition to property taxes of $2 million each year.

"We are light years ahead of other institutions in our willingness to contribute," she said.

But some say the goodwill gesture doesn't go far enough. "We certainly appreciate the payment, but realistically it is a token amount when you consider the demands on the city," said City Councilor David E. Sullivan.

"[Harvard] is providing vital services to students, faculty, and the country, but I don't see why the city ought to be the one who's subsidizing it," Sullivan said. "Historically, it's a very small fraction of what the taxes would be."

According to City Assessor James T. McDavitt, the contribution is based on taxrates that would have been paid had the academicproperty not been exempt. "Harvard doesn't like toadmit that they're paying on that formula," hesaid.

Harvard's real estate holdings, including 1500affiliated housing units and 1000 rent controlunits, also account for a substantial chunk of theUniversity's annual payments.

Harvard Real Estate (HRE), which manages theproperty, pays between a 17 and 20 percent tax onapartments and commercial holdings. "TheUniversity has an agreement with Cambridge wherethe city takes some of our gross revenues," saidSheldon G. Tandler, treasurer of HRE.

By adding properties to its portfolio, Tandlersaid that the University actually increased moneysreceived by Cambridge although many Universityholdings are tax-exempt. The in-lieu-of-taxcontribution is often paid for "properties whichhistorically were not on the tax rolls," Tandlersaid.

The rest of Harvard's Cambridge tax bill, whichis the fourth largest in the city, comes inpayments made on utilities and non-academicproperties. The University pays approximately$300,000 in user fees for water and sewageservice.

Harvard also makes a variety of payments to theCity of Boston, including a $750,000in-lieu-of-tax payment for the 475-unit SoldiersField Park apartment complex.

The Medical Area Total Energy Plant, located indowntown Boston, is another hole in theUniversity's pocket, accounting for about $3million in yearly taxes.

Despite the complexities of the process, theUniversity has at least one advantage over theindividual taxpayer. Its bill doesn't come dueuntil May