I may have to file an extension as I do not have my W2 yet. How do I estimate my taxes for the extension w/o that information? If I get my W2 in time, no extension.

[KrisD]

Your employer was required to have your W-2 available to you by January 31st. Contact them for a copy. 

You can file for an extension, it's free. You can start a return and use your end-of-year totals found on your last pay-stub to ESTIMATE your tax liability. If you will owe, you'd be safe to pay about 10% more as a cushion. 

If you do pay and file an extension, be sure to report that payment when you finally do file for 2018. 

[rollingrocker]

Thank You