Hello,
I have similar question: I live and work 80% of the time in Oklahoma for a company in Maryland. My payroll check gets MD taxes held out of it. So when I file state will I have to file both states? Is there any formula to figure how much extra I may need held out to account for the offset of the two states? Or is there any other options?
Thanks

You need to have your company withhold Oklahoma taxes if that where you spend the bulk of your time.

80% of your pay will be taxed by Oklohoma.

If you retain a resience in Maryland, then you will pay Maryland taxes on 100% of your salary, but Maryland will give you a tax credit for the taxes paid to Oklahoma.

If you believe that you will need professional help filing this year, this IS what I do. Please double-click on my name (Atlanta Tax Expert) above to access my profile. You will find my email address in the signature portion of the profile (scroll down to the BOTTOM of the page).