If you applied all or part of your federal refund in 2015 to your 2016 return and you used TurboTax last year and transferred your information to 2016, we know this information.  If you are new to TurboTax or wish to verify the amount, go to the "federal taxes" tab, then "deductions and credits."  Select “I’ll choose what I work on” then "Estimates and Other Taxes Paid" and you'll see a topic titled "other income taxes."  One the next screen there is a section (“2015 refund applied to 2016”) to enter or verify the amount applied to your 2016 federal return.

Depending on your income level, Social Security benefits can be up to 85% taxable.  The program will calculate how much is taxable.