Maryland state income tax why am I charged an interest for tax underpayment

[gkhuat]

I am filing my tax return for 2021 and I moved to Maryland during 2021. In total I am a Maryland part year resident for 4 months.

My Maryland state income tax was withheld from my paycheck by my employer every two weeks during 2021. I found out now that I owe around $1200 local and state income tax to Maryland, but I am confused why I am charged an interest ? The tax filing due date is April 18th, 2022 and it is still February 2022. I tried using the interest calculator on their website and even that said I do not owe interest if the tax filing due date is April 18th and I file my tax before that. Was there a different state tax filing date for Maryland ? 

[LenaH]

No. Since you owe $1,200 on your state tax return, you are being subject to interest. Maryland is a pay-as-you-earn state. If your employer does withhold enough Maryland taxes from your pay, you may still be required to make quarterly estimated income tax payments if you develop a tax liability that exceeds the amount withheld by your employer by more than $500.

Per Form 502UP (Line 10), if you are a first-time filer in Maryland, you have to pay at least 90% of the current year's tax to avoid interest. 

[LenaH]

No. Since you owe $1,200 on your state tax return, you are being subject to interest. Maryland is a pay-as-you-earn state. If your employer does withhold enough Maryland taxes from your pay, you may still be required to make quarterly estimated income tax payments if you develop a tax liability that exceeds the amount withheld by your employer by more than $500.

Per Form 502UP (Line 10), if you are a first-time filer in Maryland, you have to pay at least 90% of the current year's tax to avoid interest.