Remember you have until you file your tax return (excluding extensions) to make a contribution to a Traditional IRA or Roth IRA. This is typically April 15th following the end of the plan contribution year.
The annual contribution amount is $5,500 or $6,500 (if you are age 50 or over). Prior to making the contribution, if you (or your spouse) are an active participant in an employer's qualified retirement plan, you will want to make sure your modified adjusted gross income (MAGI) does not exceed certain income thresholds.
Note: Married IRA limits depend on whether either you, your spouse or both of you participate in a qualified employer provided retirement plan. If married filing separate and either spouse participates in an employer's qualified plan, the income phase-out to contribute is $0 - $10,000.
If your income is too high to take advantage of these IRAs you can always make a non-deductible contribution to an IRA. While the contributions are not tax-deferred, the earnings are not taxed until they are withdrawn.