For 2014, if you are married, up to 85% of your Social Security benefits may be taxable if your income exceeds a "base amount." The base amount takes into account one-half of your combined Social Security benefits, plus your taxable pensions, wages, interest, dividends and other taxable income, plus any tax-exempt interest and some other excludable income... listed in IRS Publication 915.
For 2014, unless changes are made, the base amount is as follows:
•$25,000 if your filing status is single, head of household or qualifying widow(er).
•$25,000 if you are married filing separately and lived apart from your spouse for all of 2013.
•$32,000 if your filing status is married filing jointly.
•$0 if you are married filing separately and lived with your spouse at any time during 2013.