It’s not too late to lower your tax bill for 2015. If you haven’t filed your taxes yet, you may be able to reduce your adjusted gross income by up to $6,500. These tax deductions, in turn, reduce the amount you owe Uncle Sam.

There are three options to lower your tax bill, all of which take the form of a contribution, either to your retirement account or a health savings account. All can be funded up to this year’s tax deadline of April 18 (April 19 for Massachusetts and Maine): 

Contribute to a traditional IRA. The easiest way to lower your adjusted gross income is by adding to your retirement savings through an IRA. You can contribute up to $5,500—$6,500 if you’re over age 50—and the deduction will apply to your 2015 taxes if you make the contribution before this year’s tax deadline.

Something to keep in mind: Your deduction from an IRA contribution could be reduced or eliminated if you or your spouse is covered at work by a retirement plan like a 401(k), and your income exceeds certain limits

Note, too, that this tax break only applies to a traditional IRA—one in which your contribution comes from pre-tax income. While you can still open or add to a Roth IRA to apply toward tax-year 2015 (if your earned income is less than $193,000 for married couples filing jointly or $131,000 for singles and heads of household), contributions to a Roth IRA are not tax-deductible. The result is that it would not lower your tax bill for 2015. 

Contribute to a SEP IRA. If you made money from self-employment last year, you can lower your tax bill by contributing to a Simplified Employee Pension Individual Retirement Arrangement (SEP) IRA. The SEP IRA allows you to put aside up to $53,000 or 25 percent of your income—whichever is smaller—regardless of whether you’re covered by a retirement plan at your main job.

While you may contribute to both a SEP and a traditional IRA in the same tax year, because of their tax-advantaged nature, the amount of the traditional IRA contribution that you can deduct on your income tax return may be reduced or eliminated if you contributed the maximum allowed to your SEP IRA.

Contribute to an HSA. Health Savings Accounts (HSAs) are accounts that you can create and fund in conjunction with high-deductible health insurance plans. An individual can allocate up to $3,350 for 2015, which must be contributed before this year’s tax-filing deadline; families can fund their account up to $6,650. You can draw on the account to pay for out-of-pocket health care costs. The money in the HSA is yours to keep and use, even if you switch plans. 

There are three ways to fund an HSA and lower your tax bill. Your employer may have elected to contribute directly to your 2015 HSA; that contribution is not tax-deductible. You might have made pre-tax contributions, deducted from your own income, up to December 31, 2015. And if you haven't reached the contribution limit, you can make post-tax contributions directly to the HSA, up to the 2016 filing deadline. 

Whether pre-tax or post-tax, your contributions are eligible for a 2015 tax deduction if your health plan meets certain criteria. For a plan to be HSA-eligible, it must not cover any health care costs (except preventive care) before the deductible is met. If your plan covers doctor visits with a copay before the deductible is met, it's not HSA-eligible—and you won’t be able to take advantage of the tax-deductible contribution. 

To contribute post-tax dollars, you'll need to send a check or arrange for an electronic transfer directly to the company managing your HSA account, indicating that it's for tax-year 2015. Tax software or a tax professional can guide you to ensure that the additional contribution counts toward your deduction on your tax return.