If you are not married on December 31st and you were responsible for the upkeep of a household for a child, parent or other relative, you may be eligible to file your tax return using the head of household status.
If you are legally married, but have spent the last six months of the year in a separate residence from your spouse, you can be considered unmarried and may be able to qualify for head of household.
In order to qualify to file as head of household, you must comply with the following requirements:
You are either unmarried or considered unmarried due to residence at the end of the year.
You incurred over half of the expenses related to maintaining a home for the year, for yourself and another qualifying person.
Aside from your parents, who are not required to live with you, any other qualifying person has to reside in your house with you for more than half of the year. Temporary absences are excused.