A Sneak Peek at 2014 Taxes / Forecasting next year's IRS inflation adjustments, which affect tax brackets and more.

Laura Saunders  for the Wall St Journal writes: Inflation might be tame, but it still is going to affect your taxes next year.

The Internal Revenue Service won't release the official numbers for inflation adjustments to tax-code provisions affecting individuals in 2014 until later this year. But some experts have released their own projections.

James Young, the Crowe Horwath professor of accountancy at Northern Illinois University, and specialists at tax publisher CCH, a unit of Wolters Kluwer,WTKWY +0.46% say the official inflation rate used to adjust the numbers will be about 1.6%, lower than last year's 2.5% rate and 2011's 3.8% rate. Their estimates are based on data released by the U.S. Department of Labor.

Most taxpayers will experience modest savings from inflation indexing, says Mark Luscombe, principal analyst at CCH. A married couple filing jointly who have $100,000 of taxable income, for example, will owe about $145 less for 2014 compared with 2013 because of tax-bracket indexing, and they also will realize small gains from changes to the personal exemption and the standard deduction.

Congress added the adjustments to the tax code starting in the late 1980s in an effort to prevent taxpayers from owing more simply because inflation pushed them into higher brackets and eroded benefits. Many—but not all—provisions are adjusted annually.

Investment Income Surtax

Notable provisions that aren't indexed include the new 3.8% surtax that applies to net investment income and the 0.9% Medicare tax on earned income. Both take effect at $250,000 of adjusted gross income for married joint filers ($200,000 for single filers).

"Over time, this will be a killer," Mr. Young says.

The $3,000 limit for using capital losses to shelter ordinary income, such as wages, also isn't indexed for inflation. Nor are income limits for the American Opportunity Credit, which for many people is the most valuable education benefit. It phases out for most joint filers with adjusted gross income above $160,000 ($80,000 for single filers).

However, two lapsed provisions that Congress reinstated starting in 2013 are indexed for inflation: the personal-exemption phaseout and the limitation on itemized deductions.

Each limits the value of certain tax benefits for higher-income taxpayers, and both have a current threshold of $300,000 of adjusted gross income for joint filers ($250,000 for single filers). This will rise a few thousand dollars in 2014, Mr. Young says.

AMT Exemption Rises

Also in 2013, lawmakers permanently indexed the alternative minimum tax for inflation. Until the change, Congress had to pass one- or two-year patches to keep inflation from greatly expanding the AMT, a separate levy that rescinds the value of some benefits.

The current $80,800 exemption for joint filers is expected to rise to $82,100 in 2014. For single filers it will rise to $52,800 next year from $51,900 this year.

In many cases, inflation adjustments are rounded down to the nearest $50, Mr. Luscombe says, but special conventions apply in others. Contributions to individual retirement accounts and Roth IRAs are adjusted for inflation, but not until the cumulative increase reaches $500. No change to the $5,500 contribution limit is expected for 2014, although some income phaseouts will rise slightly, says Mr. Young.

The annual gift-tax exclusion rises with inflation in $1,000 increments. In 2013 it rose to $14,000 from $13,000, where it had been since 2009, and it won't change next year.

For individuals, the largest change in 2014 will be to the lifetime gift- and estate-tax exemption, which lawmakers made permanent and indexed for inflation this year. Both Mr. Luscombe and Mr. Young expect it to rise to $5.34 million per person in 2014, compared with $5.25 million this year.