When the state Department of Revenue decided this year that same-sex couples in South Carolina must file separate state tax returns - even if they file a joint federal return - it likely gave some of these couples a tax break.

In certain cases, depending on a same-sex couple's income and finances, they could pay less state tax by filing separately.

However, accountants caution that the situation is complicated, and it's difficult to know how many will save money and how many will pay more.

And even couples who pay less state tax might see that savings wiped away by the extra cost of having to prepare and file two separate federal tax returns - a joint return for the Internal Revenue Service and a pro-forma individual federal return for the S.C. Department of Revenue.

"It's so hard to box things in," said Chuck Talbert, a CPA with Webster Rogers. "Each individual situation would just be so different. I'll be honest, I have not actually encountered this yet."

Steven Clem, owner of Charleston Tax Masters, has worked with such returns and said, "Certainly there are going to be situations out there where a (same-sex) couple is saving a little money on the state tax. And there are situations out there where it won't make any difference."

At the federal level, most couples who get married and who both work find it more tax expensive. South Carolina tax rates are the same no matter what a person's filing status. They are graduated and reach a maximum of 7 percent at $14,250 of taxable income.

If two single state residents each had a taxable income of $14,250, then each would pay $513 in state taxes, or a total of $1,026.

But if these same residents were married, their combined income would be $28,500 - and their state tax would come to $1,510, an increase of $485. The state's two-wage earner credit that is capped at $210, so their net increase by filing jointly would be $275.

But there is no couple exactly like that, and other differences can create a different set of outcomes.

"It's hard to give just a generic answer in the whole tax realm, it's gotten so complex," Talbert said, "and this only adds to the complexity, of course."

Warren Redman-Gress, a Charleston resident and director of the Alliance for Full Acceptance, was told he and his partner had to file a joint federal tax return this year because of the U.S. Supreme Court's June decision in the Windsor case. And that caused them to pay more in federal taxes.

Redman-Gress said they also will pay more to prepare separate federal returns for the state, but they haven't figured out if they will pay more or less in state taxes.

Even if it's less, Redman-Gress said he will pay more to prepare his returns two different ways. "The state is putting us in a bind because the federal government is requiring us to file jointly," he said. "The state requires people to file as we file federally - with the exception of gay couples."

Clem agreed that any savings to same-sex couples likely would be erased by the burden of having to redo their federal income tax. "If you're in a same-gender marriage, you're going to create five returns just so you can file three of them."

Oran Smith with the Palmetto Family Council, a conservative group that backs the traditional marriage, said his group did not weigh in on the state's decision to require same-sex couples to file separate forms.

Asked about how he felt that some same-sex couples may pay less, he said, "As a taxpayer myself, I'm always in favor of anyone paying less in taxes, so that sounds like a good thing to me, to us."

Redman-Gress said the tax code is tailored to benefit one-income married couples, and he has heard from many gay couples who are paying more in federal taxes this year as a result.

"I am sure there are gay and lesbian couples who are grinding their teeth about this whole marriage equality thing," he said, "but I've yet to find anyone who has said, 'I wish the federal government hadn't done this.'"

Reach Robert Behre at 937-5771.