What is the tax rate for selling stocks?
Assuming that taxes were withheld when you received the options, you would now only owe tax on the profit from the sale of the stock.  The cost basis would be whatever you bought the stock for (the strike price of the options in this case), and the profit will be the total amount received from the sale minus the total cost of those shares. Since you bought the stock more than one year ago, you will get taxed at the long-term capital gains rate of 15% (unless you are in the 39.6% tax bracket, in which case the rate is 20%). As with all tax advice on this site, you need to check with a tax specialist when you actually file, but that should give you a rough indication of what your tax liability is.