For a Traditional IRA (Filing Status Married Filing Jointly or Qualifying Widow(er)):
If you are not covered by a retirement plan at your job and your spouse is not covered by a retirement plan, there is no MAGI limitation on your deductible contributions.
If you are covered by a retirement plan at work, and your MAGI is $98,000 or less, there is also no limitation on your deductible contributions to a traditional IRA.
If you are covered by a retirement plan at your job and your MAGI is more than $98,000 but less than $118,000, you are entitled to a partial deduction, reduced by 27.5% for every dollar over the lower limit (or 32.5% if over age 50), and rounded up to the nearest $10. If the amount works out to less than $200, you are allowed to contribute at least $200.
If you are covered by a retirement plan at your job and your MAGI is more than $118,000, you are not entitled to deduct any of your traditional IRA contributions for tax year 2015. You are eligible to make non-deductible contributions, up the annual limit, and those contributions can benefit from the tax-free growth inherent in the IRA account.
If you are not covered by a retirement plan at your job, but your spouse IS covered by a retirement plan, and your MAGI is less than $183,000, you can deduct the full amount of your IRA contributions.
If you are not covered by a retirement plan but your spouse is, and your MAGI is greater than $183,000 but less than $193,000, you are entitled to a partial deduction, reduced by 55% for every dollar over the lower limit (or 65% if over age 50), and rounded up to the nearest $10. If the amount works out to less than $200, you are allowed to contribute at least $200.
Finally, if you are not covered by a retirement plan but your spouse is, and your MAGI is greater than $193,000, you are not entitled to deduct any of your traditional IRA contributions for tax year 2015. You are eligible to make non-deductible contributions, up the annual limit, and those contributions can benefit from the tax-free growth inherent in the IRA account.
For a Roth IRA (Filing Status of Married Filing Jointly or Qualifying Widow(er)):
If your MAGI is less than $183,000, you are eligible to contribute the entire amount to a Roth IRA.
If your MAGI is between $183,000 and $193,000, your contribution to a Roth IRA is reduced ratably by every dollar above the lower end of the range, rounded up to the nearest $10. If the amount works out to less than $200, you are allowed to contribute at least $200.
If your MAGI is $193,000 or more, you cannot contribute to a Roth IRA.