9 Costly Mistakes Taxpayers Make

For as much as Americans complain about paying taxes, we sure leave a lot of money on the table—thanks to poor tax planning, sloppy filing and the sheer complexity of the tax code.

Feeling exhausted.
(Image credit: Thinkstock)

For as much as Americans complain about paying taxes, we sure leave a lot of money on the table—thanks to poor tax planning, sloppy filing and the sheer complexity of the tax code. Last year, the IRS reported that it was holding on to $1 billion in unclaimed refunds for folks who didn't file a tax return in 2011.

Some taxpayer mistakes, such as providing the wrong Social Security number on your return, will simply delay processing of your return (and, potentially, your refund). But other mistakes, including the nine featured here, may cost you more than time. Plan ahead and take extra time with your return to avoid these expensive taxpayer errors.

Kevin McCormally
Chief Content Officer, Kiplinger Washington Editors
McCormally retired in 2018 after more than 40 years at Kiplinger. He joined Kiplinger in 1977 as a reporter specializing in taxes, retirement, credit and other personal finance issues. He is the author and editor of many books, helped develop and improve popular tax-preparation software programs, and has written and appeared in several educational videos. In 2005, he was named Editorial Director of The Kiplinger Washington Editors, responsible for overseeing all of our publications and Web site. At the time, Editor in Chief Knight Kiplinger called McCormally "the watchdog of editorial quality, integrity and fairness in all that we do." In 2015, Kevin was named Chief Content Officer and Senior Vice President.