Still working on your taxes?

If so, I've got a last-minute checklist of things you can still do to lower your bill or raise your refund, and a few reminders about some often-overlooked tax breaks.

One of the quirky things about the federal tax code is how some things can be done retroactively. For example, you can't change what you earned last year or how much tax was prepaid during 2012, but you have until April 15 to reduce last year's taxable income with IRA contributions.

That's no secret, but what people often forget is that the benefit can be greater than simply being able to deduct the contribution.

For example, reducing your taxable income could allow you to avoid a penalty if you didn't have enough tax withheld from your pay in 2012.

Reducing your taxable income also could make you eligible for tax credits that depend upon your income.

Double benefits

Let's say you're married (filing a joint return), and you and your spouse both worked in 2012 and put some money into 401(k) plans or other retirement accounts, and the adjusted gross income you're going to report on your federal tax return is $58,000.

With just a small contribution to a traditional IRA, you could knock your adjusted gross income below the $57,500 threshold for a married couple and claim the federal “savers” tax credit.

By contributing just $501 to an IRA, in order to meet the income threshold, that couple would get a 10 percent tax credit for not only that small IRA contribution, but for all the retirement contributions they made in 2012, up to $2,000 each. The couple could potentially claim a $400 tax credit in addition to saving $75 by deducting their IRA contribution from their taxable income, which means it would cost them $25 to put $501 away for retirement.

That's a good example of how someone right on the edge of being able to claim a tax credit could tip themselves into eligibility by making a tax-deductible IRA contribution.

People with lower incomes can get a tax credit worth up to 50 percent of their retirement contributions.

It's been shown in many studies that middle-income and lower-income tax credits often go unclaimed because people don't know about them or don't get help filing their taxes.

The Earned Income Tax Credit and the Child and Dependent Care tax credit can put some money in your pocket if you are a lower-income working parent. So, do what wealthy people and corporations do, and make sure you take advantage of all the tax deductions and credits for which you qualify.

For South Carolina taxpayers who will soon be paying college tuition bills and related expenses like room and board, April 15 is the deadline for making a 2012 contribution to the state's 529 plan, Future Scholar.

If you put money into a Future Scholar account, you can deduct that amount from your state tax bill, which for most people is like getting 7 percent back.

So, you can put money in, get a state tax deduction, then use the funds to pay tuition, room and board, and other eligible expenses. Withdrawals and earnings from a 529 account are not taxed so long as they're used for the intended purpose.

Overlooked tax breaks

Sometimes tax breaks get overlooked because they are little-known state tax breaks or because of last-minute federal rule changes. There were lots of those in the “fiscal cliff” deal.

Also, some people overlook tax credits because they file the “EZ” federal form, which can't be used to claim some credits, including the “saver” credit.

Do you have a modest income but high homeowners insurance costs? If the cost of insuring your home in 2012 exceeded 5 percent of your federal adjusted gross income, South Carolina has a tax credit for you worth up to $1,250, the “excess insurance premium credit.” I keep mentioning this one in my column because so few people seem aware of it.

Did you buy a hybrid or clean-diesel car last year? South Carolina has a tax credit for that, which even car dealers don't seem to know about. It's called the “alternative vehicle motor credit.” For example, if you bought a Toyota Prius last year, you're due for a $630 tax credit.

Did you insulate your residence, install efficient windows or update your heating/cooling system in 2012? The “fiscal cliff” deal revived an expired 10 percent tax credit for the cost of such materials, worth up to $500 in tax savings.

Those tax deductions and credits can really add up, so make sure you're getting the ones you're due.

Reach David Slade at 937-5552 or Twitter @DSladeNews.