You may be able to file as head of household if you meet all the following requirements.
1. You are unmarried or “considered unmarried” on the last day of the year.
(You could be considered unmarried if your spouse did not live in your home at any time during the last 6 months of the tax year).
If you were considered married for part of the year and lived in a community property state, special rules may apply in determining your income and expenses. See Publication 555 for more information.
2. You paid more than half the cost of keeping up a home for the year.
3. A “qualifying person” lived with you in the home for more than half the year (except for temporary absences such as school) - a parent does not have to live with you to be a qualifying person.
4. If the qualifying person is your qualifying relative, their gross income must have been less than $4,050 (do not include non taxable Social Security) and you provided more than 1/2 of their support
5. You must be able to claim the exemption for the qualifying person except in the case of divorced or separated parents (that lived apart) and the noncustodial parent is claiming the exemption.
A Qualifying person is either:
A qualifying child or a qualifying closely related relative and meets certain other requirements, however if you are considered unmarried it can only be your child, stepchild, or foster child.
See IRS Publication 17 for more information about who is a qualifying person and a worksheet to determine the cost of keeping up a home.
See IRS Pub 17 for more information
---Tests to be a Qualifying Relative (& Unrelated Persons)---
(Must meet ALL of these tests to be a dependent)
1. The person cannot be your qualifying child or the qualifying child of any other taxpayer.
2. The person either must be related to you, or must live with you all year (all 365 days - There are exceptions for temporary absences such as school, illness, business, vacation, military service) as a member of your household.
3. The person's gross income for the year must be less than $4,050 (tax-exempt income, such as certain social security benefits, is not included in gross income)
4. You must provide more than half of the person's total support** for the year.
5. The person is not filing a joint return.
In any case, the person must be a U.S. citizen, U.S. resident alien, U.S. national, or a resident of Canada or Mexico
The above is simplified; see IRS Publication 17, for full information.
** Worksheet for determining support