My understanding is that Social Security benefits are not taxable at all in New York State. Why are part of my Social Security benefits taxable in New York State?

You are correct. Per NYS, social security benefits that are included in federal adjusted gross income are exempt from New York state and local income taxes and may be subtracted from your federal adjusted gross income when computing your New York adjusted gross income. Where are you seeing that your social security benefits are taxable in NYS? 

 

On the screen titled Your New York Income Adjustments, you should see that your social security is being deducted from your federal income. I have attached a screenshot for additional guidance.

 

 

 

Publication 36

 

 

 

Thank you.  I see The adjustment for Social Security but it was for less than the full amount of the benefits I received.  

0-85% of your Soc Sec benefits are taxable for Federal, so the NYS subtraction is for the taxable amount, not the gross amount.