It is tempting for people who earn less than $400,000 to think that they got off easy this week under the tax deal to end the fiscal impasse, given that only those with incomes above that level will be in a higher income tax bracket in 2013.
But the legislation that both houses of Congress have now approved could increase taxes on people with incomes that are not quite that high as well. That's because the bill includes language that begins to do what both President Obama and Mitt Romney proposed at various points in the past: Limit certain tax breaks available to people who are affluent.
The new rules target two tax breaks: personal exemptions and many popular deductions like those for state and local taxes, mortgage interest and charitable contributions. For both breaks, single people with at least $250,000 in adjusted gross income and married people filing jointly with at least $300,000 in income are vulnerable. A hypothetical Texas couple could end up paying about $2,500 more in taxes, for instance.
The mechanics of how the new limits will work are now clear, though it takes a fair bit of explaining to lay them out in plain English. What we don't know yet is how many people will end up paying more in 2013 than they did in 2012.
The uncertainty is tied to the fact that many of the targets of the legislation often end up ensnared by the alternative minimum tax. The A.M.T., and its high tax bill, may continue to catch most of them.
But let's start with the basics. Most of the discussion here begins with that adjusted gross income figure. That's the number you get when you subtract items from your salary or take-home pay that are often referred to as above-the-line deductions.
For the income range we're talking about, these deductions tend to include things like health savings account contributions and alimony. People who work for themselves also get deductions for health insurance premiums, certain retirement contributions and self-employment taxes that an employer would otherwise pay.
Mark Luscombe, principal analyst with CCH, a tax information provider, points out just how confusing the use of adjustable gross income is, given that the new tax limits, the new tax bracket and the new Medicare tax are all based on different definitions of income.
Under normal circumstances, a personal exemption, for a specific dollar amount, is available for each member of your household. You then add all of the exemptions and subtract the total from your adjusted gross income, which has the effect of lowering your taxable income. CCH predicts that the personal exemption amount for 2013 will be $3,900 per person.
The new law requires taxpayers in the targeted income range to reduce the amount of their exemptions by 2 percent for every $2,500 by which their income exceeds the $250,000 or $300,000 limit. So a married, childless couple with $400,000 in adjusted gross income and $7,800 in potential exemptions could lose $6,240 of that $7,800.
The math for the limit on deductions is different. There, the rules call for you to add up the applicable deductions. Let's say that equals $50,000. Then, you subtract from that 3 percent of the amount by which your adjusted gross income exceeds those $250,000 or $300,000 thresholds.
