I claim two on my W-4 and am single and you still owe on taxes how many should you claim?

Eork through the examples and outlines provided in the instructions for form w-2...it may take a little thought and time...and it will give a good reasonable # of dedcutions that should get your withholding fairly close to where it needs to be. Obviously, if through the year your situation changes...for example you pick a few good stocks and sell them...that amount may need to change.