I only lived in Alabama 3 months. My former state of residence was Tennessee, no state taxes. How do I determine how much taxes I owe Alabama?

Part year residents whose filing status is:

1.  Single” must file if gross income for the year is at least $4,000 while an Alabama resident.
2. “Married Filing Separate Return” must file if gross income for the year is at least $5,250 while an Alabama resident.
3. “Head of Family” must file if gross income for the year is at least $7,700 while an Alabama resident.
4. “Married Filing Joint Return” and whose gross income for the year is at least $10,500 must file an Alabama Individual Income Tax Return while an Alabama resident.

You would file Alabama part-year resident return and report only the income earned while you were Alabama resident. 

How do I file a part-year state return?

To allocate your income, select the type of income and follow instruction from the link below:

How do I allocate (split) income for a part-year state return?