For a Traditional IRA (Filing Status Single or Head of Household):
If you are not covered by a retirement plan at your job, there is no MAGI limitation on your deductible contributions.
If you are covered by a retirement plan at work, if your MAGI is $61,000 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 $61,000 but less than $71,000, 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.
If you are covered by a retirement plan at your job and your MAGI is more than $71,000, 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 Single or Head of Household):
If your MAGI is less than $116,000, you are eligible to contribute the entire amount to a Roth IRA. If your MAGI is between $116,000 and $131,000, 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 $131,000 or more, you cannot contribute to a Roth IRA.