This is an especially dangerous issue for 2012 returns because, throughout 2012, this tax deduction simply didn't exist.
The right for taxpayers to deduct state sales taxes paid expired at the end of 2011. Everyone expected Congress to revive the tax break sometime during 2012, but the issue got tangled up in fiscal cliff negotiations. Finally, in the bill approved Jan. 1, 2013, the deduction was restored ... retroactively for 2012 and for 2013 returns that will be filed next year.
This is particularly important to you if you live in a state that does not impose a state income tax. You see, Congress offers you the choice between deducting state income taxes paid or state sales taxes paid. You choose whichever gives you the largest deduction, of course, and if your state doesn't have an income tax, the sales tax write-off is clearly the way to go.
In some cases, even filers who pay state income taxes can come out ahead with the sales tax choice. The IRS has tables that show how much residents of various states can deduct, based on their income and state and local sales tax rates. But the tables aren't the last word. If you purchased a vehicle, boat or airplane, you may add the sales tax you paid on that big-ticket item to the amount shown in the IRS table for your state.
The same goes for any homebuilding materials you purchased. These add-on items are easy to overlook, but could make the sales-tax deduction a better deal even if you live in a state with an income tax. The IRS has a calculator on its website
to help you figure the deduction.