For 2014 and 2015, Roth IRA contributions are only limited if taxable compensation is less than $5,500 ($6,500 for persons 50 years of age and older). In such cases, contributions are limited to the amount of taxable compensation. Otherwise, contributions are limited to $5,500 of $6,500, regardless of income.
Additionally, contributions to a Roth IRA may only be made by individuals with taxable compensation whose modified adjustable gross income is less than the threshold designated by the IRS. For a married person filing jointly or qualified widow(er) the limit is $191,000.
Single, head-of-household filers and those married who are filing separately that did not live with their spouse during the year are limited to earnings of $129,000; married persons filing separately that lived with their spouse at any time of the year may not contribute if earnings exceeded $10,000.