Middle-class suburban New Yorkers, senior citizens, and single residents are the big winners in Eliot Spitzer’s new tax plan, an examination of his proposal shows.

Under the Democratic gubernatorial candidate’s tax plan, New York City residents would receive a tax cut a fraction of the size of the one he would give to suburban homeowners. The attorney general’s proposal also favors single New Yorkers over married couples and reduces property taxes for millions of middle-class residents while extending little or no relief to wealthier residents.

After being goaded by his opponents for months, Mr. Spitzer on Monday came out with his first detailed tax-cutting proposal, a $6 billion package over three years that would direct state funds to homeowners to offset their soaring school tax burden.

His opponents in the governor’s race, John Faso, a Republican who served in the Assembly, and Thomas Suozzi, a Democrat who is the Nassau County executive, had been trying to portray him as a typical tax-and-spender. They claimed Mr. Spitzer would ignore the plight of suburban homeowners, many of whom have seen their property tax bills rise at a rate of 6% a year.

Political analysts say the best hope of Messrs. Faso and Suozzi to gain on the attorney general, the front-runner in the race, is by making an appeal to Democratic voters in suburban counties like Westchester, Rockland, Nassau, and Suffolk – a demographic seen as more conservative than New York City voters and more sensitive to the issue of taxes.

Messrs. Faso and Suozzi have attacked Mr. Spitzer’s plan on various grounds. They say the plan cannot be effective because it doesn’t put a cap on school spending and thus school taxes. They also have cast doubt on how Mr. Spitzer would pay for it. The candidates have proposed their own property tax plans, which also favor suburban residents. The Spitzer campaign says the city would see no new aid under Mr. Suozzi’s property tax plan.

By also gearing his tax cut plan toward suburban voters, Mr. Spitzer, a resident of the Upper East Side, appears to be trying to neutralize his rivals’ criticism that he doesn’t care about the suburbs.

“It makes a lot of sense politically,” said a Democratic consultant, Hank Sheinkopf, who worked for Mr. Spitzer’s 1998 campaign for attorney general. “If there’s politics in this, the politics are to get the suburbs alerted to the fact that Spitzer is on their side and not just concerned about New York City.”

A look at the impact of Mr. Spitzer’s plan, using data supplied by Mr. Spitzer’s campaign, shows how geography, income, and age of recipients matter greatly. Mr. Spitzer’s plan essentially piggy-backs on Governor Pataki’s nine-year-old School Tax Relief program, or STAR, which uses state tax dollars to give homeowners a partial exemption on their property taxes.

Mr. Pataki’s program gives the biggest exemptions to homeowners in suburban counties, which have the highest property tax rates, and to middle-class senior citizens. New York City residents, who pay less property tax but pay local income taxes, have benefited less from the program than homeowners in other regions.

Mr. Spitzer takes the same formula Mr. Pataki has relied on and infuses it with money, which has the effect of widening the disparity of benefits between New York City and the suburbs. He also makes it means-tested. As it is now, non-senior-citizen homeowners in the same county received the same tax break, regardless of their incomes. Under Mr. Spitzer’s plan, a homeowner’s income has a large impact on the size of the benefit. If you’re among the top 2% of earners, you won’t see any additional tax relief.

Because Mr. Spitzer’s plan counts combined household incomes against the savings thresholds, homeowners are better off filing separately than filing a joint return.

New Yorkers with gross adjusted (not taxable) incomes at or below the statewide median – a range of $60,000 to $90,000 – would see their property tax exemptions increase by 80%. The exemption would decline gradually on a sliding scale for recipients above the median point.

Homeowners with incomes twice the median amount but under $235,000 would see their exemptions go up by 30%. Those with incomes greater than $235,000 would get no additional relief.

Senior citizens with incomes under $67,851 – a demographic that already is eligible for the largest exemptions under Mr. Pataki’s program – would see their exemptions go up by 30%.

Here’s how it would translate into actual savings in the first year of the Spitzer program:

* A Westchester single resident with an adjusted gross income of $90,000 would see an additional reduction under Mr. Spitzer’s plan of $1,472, regardless of the value of the home. A New York City resident with the same income would save $251.

* Mr. Spitzer would cut the taxes of a Westchester senior citizen homeowner making $67,850 or less by $918. A New York City senior citizen would see a reduction of $189.

* A New York City married couple with a combined income of $235,001 wouldn’t see any new benefits.

The Spitzer campaign argues that their formula makes Mr. Pataki’s program more equitable.

“It fixes a major problem with STAR – that it currently does not distinguish between the middle class and the millionaire,” said a spokeswoman for the campaign, Christine Anderson.

Aides also say Mr. Spitzer’s plan does not have a marriage penalty but spreads out benefits based on the capacity of homeowners to pay their taxes. Incomes ought to be combined, they argue, because both sources of money are going to pay the same single property tax bill.

“The whole point of this plan is that it goes to people who need it most and it’s based on their ability to pay,” Ms. Anderson said.